Jan van Eyck

was credited by the 16th century artist and biographer Vassari as the inventor of oil painting. That's not the case, but in the early 15th century he was one of the pioneers of the modern use of oil painting as a primary painting medium.



Apparently, he had a sense of humor. This painting, which may be a self-portrait, was made with a frame carved as part of the panel. At the bottom, it's inscribed (in Greek letters in the Flemish language) with what appears to be a pun. It can be read either as "As I can," or "As Eyck can."

Getting back to drawing the figure

Since the Summer, Kiri and I haven't been able to attend figure drawing and painting classes at the New England Realist Art Center. She got too pregnant, then she had Brendan, who does make things more difficult.

We have been attending sessions on Monday nights of the Worcester figure drawing group at Worcester State College (actually, we've been alternating weeks while the other one watches the kid). An open figure drawing session is very different. First, there's no instruction. Second, it's a lot cheaper. Third, poses run from one minute to fifteen minutes. At NERAC, poses run for four or five three hour sessions. So it's been a bit of an adjustment.

Archival permanence

Over time, all paintings deteriorate. Badly made paintings deteriorate quickly, sometimes within a year or two of completion. A painting made with a high level of craftsmanship can last for many years before noticeable changes occur.

For most of us, it isn't worth going to extreme lengths to make our paintings as permanent as they can possibly be. You could, for example, choose to paint on high-tech aluminum honeycomb panels. These are light, long-lasting, and much better supports for painting than most of those used by artists, because they don't significantly expand or contract with changes in temperature and humidity. They also cost hundreds or thousands of dollars. If you know that you are a visionary artist who will be producing work of breathtaking magnificence that will be of incredible historic significance, you owe it to future generations to eat only cheap prepackaged noodle dishes at each meal so that you can afford to paint on the most permanent and expensive supports (until you work starts to sell for many thousands of dollars—then, go ahead and treat yourself to a nice juicy tofu burger).

For the rest of us, not so much. Most paintings by even fairly good artists won't be saved for much more than a generation. The best way to preserve your paintings is to make them really, really good (or really, really popular, which 20th century artists demonstrated to have no correlation with good). A painting that people like a lot will be hung on a wall in a room that has a reasonably constant temperature and no wild swings in humidity. Almost any painting will survive for a long time under those conditions. And if people really like it, it might hang in a museum or get restored by a conservator if it starts to show signs of wear and tear. If a painting isn't that great, then even if it's made with excellent crafstmanship and highly archival materials it's likey to be kept in the attic, basement, or garage for years at a time. Even well-made paintings won't last long under those circumstances, and when they start to fall apart, no one will pay for a conservator to fix them. So the most archival quality a painting can have is to be so well-liked that the owner (and the owner's heirs) could never imagine putting it in a moldy basement.

(Of course, if you are a very famous celebrity such as Sir Paul McCartney, your incredibly bad vanity paintings will be treasured and preserved for centuries. Go figure.)

Nevetheless, I think it's a smart to construct paintings with quality materials and good craftsmanship, if only so that customers won't complain until after you are dead. Here are some guidelines for oil painting. If you don't follow them perfectly, it won't cause your painting to explode. But the closer you adhere to them, the more likely your painting will be to last a long time under optimal conditions, or survive brief periods under poor conditions. If you want a painting to last a long time under poor conditions, oil paint is a very bad choice of medium.

• Rigid supports are better than fabric supports. Fabric is flexible, and every time it flexes (as it will do when temperature or humidity changes) the bond between the support and the paint is affected. Over time, that's very bad for a painting. Copper, steel, and aluminum panels are excellent supports for painting (although they can be heavy). Wood is OK only if it has been seasoned for a year or two after being cut and planed to size. Hardboard is probably OK if there is a good barrier between the panel and the paint. Tempered hardboard is stronger than untempered and that makes it better (despite what some sources say) even though there is a slight amount of oil in the surface of tempered hardboard. Medium density fiberboard is OK only if it is very well sealed on all sides against moisture.
• It may be that polyester will turn out to be the most archival fabric, because it is more dimensionally stable than organic fabrics like linen and cotton. We don’t know yet.
• Oil grounds are good to paint on. Lead grounds are the best oil grounds, because lead is a very flexible pigment. Acrylic primer ("gesso") is probably a decent ground to paint on (we'll know for sure in 100 years) but murder on brushes. Traditional gesso is probably an OK ground on a rigid support (the hide glue in gesso is very strong, which is good, but likes to absorb water, which is bad).
• Use permanent pigments. Alizarin crimson is not permanent, especially in mixtures and when applied very thinly. Impermanent pigments will fade or become dull over time.
• If you use linen, cotton, or hemp as a support, don't put paint or oil primer directly onto it. The oil will rot the fabric. You need a barrier, such as hide glue or acrylic primer, between the paint and the fabric. Make sure the barrier covers the sides as well as the front of the canvas.
• Don't apply a lot of thick paint. Thick, heavy layers of impasto are much less permanent than thin layers (about the thickness of a layer of house paint). Several thin layers (allowed to dry in between) are much more permanent than one thick layer. A few expressive blobs of impasto here and there are not going to cause problems, but large areas of thick paint are bad.
• Linseed forms the strongest paint film of the drying oils. Walnut is less strong. Safflower and poppy are weaker still. Because the same stuff that make the paint film strong also yellows, linseed will yellow more than other oils. But go for a walk through a museum with paintings three or four hundred years old. You probably don't find yourself thinking, “Wow! those paintings now suck because they've yellowed.” (Ignore Brown School paintings from the 17th and 18th centuries that were deliberately painted with an overall dull yellowish tone.) You can barely notice the yellowing, and those paintings were almost all done in linseed. Whites are a little warm, blues turn slightly greenish. That's how bad the yellowng gets on a well-made painting. It's barely noticeable, although some paint manufacturers will try to scare you into buying special “non-yellowing” paints made with oils that are less strong. Personally, I only use paints made with linseed and, to a lesser degree, walnut. I avoid paints made with poppy and safflower. If you do use safflower oil, be aware that the kind you can get in a grocery store is almost certainly not the kind that dries properly when mixed with oil paint.
• There are a number of good reasons to avoid student grade paint, but archival permanence is not one of them. Student grade paint from a good company will be as archival as their artist-grade paint.
• It is best to not add anything to your paint—no mediums, no solvents, no nothing. If you do add stuff to the paint, add only a little bit (less than 20% of paint volume). If you add solvents, don't make the paint watery or washy, just add enough to make the paint more manageable. If you apply a layer of medium to the surface of a dried layer of paint before you paint over it, make it a very thin layer.
  
• It is best not to add metallic driers to make the paint dry more quickly. If you do add them, I think that lead napthenate is best. Add a tiny amount (like one drop from a toothpick) to a penny-sized blob of paint on your palette. Add driers only to the slow-drying pigments on your palette.
• In my opinion, it has not yet been demonstrated whether alkyd painting mediums (Liquin, Galkyd, Neo-Meglip, and so on) are sufficiently permanent. They are probably fine for single layer, direct painting. I’ve heard a couple of complaints about delamination in multi-layered paintings that may be due to use of alkyds. Some alkyd mediums can also yellow quite a bit. Personally, I don’t see any reason to paint with anything that smells like that.
• If you add solvents and oils to your paint, and you work in layers, it’s best to follow the fat over lean rule. That just means that no layer should have less oil in it than the layer beneath it. So be careful about how you use mediums and avoid painting large areas of lean paints (without much oil in them) like manganese violet over large areas of fat paints (with a lot of oil in them) like ivory black. The fat over lean rule is especially important if you paint in thick layers. In thin layers, it’s still a good idea, but less crucial.
• Varnish the painting after it is dry. By dry, I mean three months to a year after completion, depending on how thick the paint is.

Few painters (including me) work according to these guidelines all the time, and yet their paintings don’t generally fall apart rapidly. Oil painting is fairly forgiving, so long as you respect your materials and stay within a reasonable zone of craftstmanship. So long as you do that, there isn’t any reason to worry about archival permanence unless the voices in your head are very insistent that you are going to be the next Michelangelo.

Personally, I doubt that the art conservation robots in the Louvre in the year 2306 will curse my name because I used sub-standard methods requiring them to spend an extra 324.663 seconds fixing one of my paintings. But that would be really cool.

Update 10/23/06: One other point regarding how to construct paintings that will last. If you paint in multiple layers, make sure that each layer adheres to the one below it. A paint layer that is smooth and shiny is not a good surface for painting over, because the next layer of paint has no mechanical tooth to adhere to. You may want to scuff up the surface with a green kitchen scrubee pad or, if you prefer, wet sand. If you use a medium that contains a balsam such as Venice turpentine or Canada balsam, the paint will adhere better to the previous layer.

Le Café Marly

One of the restaurants at the Louvre.

Practical Color Mixing 2: Hue

In the previous post in this series on color mixing, I talked about how to mix the right value. Here I’ll talk about hue.

Identifying hue

Before you can mix the right hue, you need to figure out what hue you want to mix. That’s often kind of hard, especially with the dull, low-chroma colors that predominate in most of the visual world. Look around you. What color is the wall? A yellow-green? Or is it more of a middle yellow? How about the cable leading to your monitor? Is it black, or some very dark greyish color? If so, is it a warm dark grey or a cool dark grey? What about the shadow falling on the floor from your desk? You get the picture.

When I’m standing around waiting for something I find myself trying to identify the color of various things around me. And not just the color of the thing (the “local color”) but the color of the shadow side, the light side, and so on. I think about value and chroma as well as hue, but the hue is often the hardest to figure out. As with any other attribute of color, it’s best to think in terms of comparison of one color with others around it. Once I think I know what the color is, I consider how I would mix it. That seems like a pretty geeky thing to do (and it is) but it’s a useful exercise. We think we know what color things are, but while it’s easy to say that the sky is blue, it’s a bit more of a challenge to determine that the part of the sky beyond those clouds is a green-blue, while the sky in between the clouds is slightly purple.

Nudging

So once you know what hue you want, how do you get it? Well, if the hue is pretty close to a paint that’s already on your palette, you might be able to just tint it in one direction or another. Say you want a violet blue and you have ultramarine on your palette. Without having to think about color wheels or anything complex like that, you could simply add just a bit of a more purple color, such as dioxazine violet. That may well get you where you want to go, simply and easily. In doing this, the thing to realize is that any given paint can only go in two directions from where the hue is right now—either clockwise or counterclockwise on the color circle. Ultramarine blue can be made more violet or more green. That’s it. Cadmium orange can be made more yellow or more red. If you’re just trying to nudge the hue around a little bit, all you have to decide is which direction to go and select a color next door on the color wheel to move it in that direction.

Using a mixing color wheel

The nudging strategy is great for small adjustments, but it starts to fall apart when you need to make a hue that isn’t close to one of the paints you already have. At that point, it’s useful to go back to the concept of a color mixing wheel. As I’ve pointed out previously, a color mixing wheel does not provide a precise guide to what you will get with any two pigment mixtures. Individual pigments are simply too idiosyncratic in their mixing properties to allow any kind of absolute prediction of how they will behave when mixed. But a color mixing wheel will help you to get into the approximate ballpark, at which point you will be close enough to use the nudging aproach described above.

Steven Quiller sells a useful color mixing wheel. Bruce MacEvoy at Handprint has a somewhat different one that you can print out for free (it's designed for watercolor, but I have found it to be reasonably useful for other media as well).

Say you need to mix a yellowish green, but don’t have anything close to that on your palette. If you look at a color mixing wheel, the two colors on either side of green are blue and yellow. As we all know, you can mix a green from blue and yellow, and if you adjust the proportions correctly, you can pretty easily get a yellowish green. If you have any set of paints that are selected to fall at reasonable intervals across the color wheel (at least a cyan, magenta, and yellow), you can mix any desired hue using two or three paints.

A traditional color wheel is set up so that all of the colors on the outside are as high in chroma as that hue goes (without regard to value). On the inside are less chromatic colors, arranged so that the closer to the center they are, the lower the chroma. The basic mixing procedure goes like this: (1) identify a point within the color mixing wheel that represents the desired hue and chroma; (2) look for one or more lines between two paints that pass through (or near) the color you are trying to match; and (3) consider whether a third paint (typically one on the opposite side of the wheel from the desired color) might be needed to adjust the chroma downward. If the paints have equal tinting strength, you can figure out approximately how much of each paint you will use, based on where the desired color falls on the line between the two paints being mixed. If one paint is stronger, you’ll need to adjust accordingly to account for that. As a general rule, put out some of the weaker paint and add the stronger paint to it. Alternately, put out the paint you will use the largest amount of and add the other paint to it. Add in small increments at a time—I find myself overshooting frequently if I’m not careful.

With oil paint, it's best to mix with a palette knife rather than a brush. Once you're used to it, the knife is faster because you can clean it so quickly, and your paint piles don't become contaminated with other pigments.

Coordinating hue and chroma

Notice that if you draw a straight line between any two colors on the outside the wheel, every point on the line represents a lower chroma than those two colors. So mixing tends to reduce chroma. As a general rule, any mixture is duller than the brighter of the two paints being mixed, and often duller than either one. There are a very few exceptions (some warm pigments become a little more chromatic when mixed with each other and some cool pigments become more chromatic when mixed with a small amount of white), but chroma reduction is the usual effect of paint mixing.

Often, it’s useful to have mixing reduce chroma, because in realist painting you are frequently trying to mix a color that is duller than the tube paints you have available. If you’re trying to mix a flesh tone with bright cadmium colors, for example, any reduction in chroma is welcome (you've probably seen bad amateur portraits with bright orange flesh tones). But there are times when you are trying to mix a high-chroma color, and in that case the chroma reduction from mixing can be frustrating. Because of this effect, it’s often a bad idea to just muck around with paint, hoping to get close to the color you’re looking for. Every paint you add to the mix cuts the chroma down, so after awhile you are just mixing paint into a sort of nondescript grayish color—i.e., you're mixing "mud."

It’s is much better to decide what color you want, choose two or three paints that you will use to get that color, and try to stick with those. Minor nudging with other paints is OK, but if the mixture goes radically in a direction you didn’t expect, don’t keep throwing additional paints in, hoping you’ll eventually get to your desired color. Once you have mud, just scrape it off your palette (or use it as the basis of some nondescript color you need elsewhere) and start over. Take a step back and think again about what you’re trying to accomplish and how you’re going to get there.

As noted above, many pigments fail to follow a straight line on the color wheel when mixed. In particular, some paint mixtures follow a circular mixing line. That means that, while the wheel predicts the correct hue, the chroma is higher than expected (this is particularly common with greens). In that case, go ahead and mix the hue you want, then tone it down (I’ll talk about adjusting chroma in the next post in this series).

Coordinating hue and value

We’ve talked about getting to the right hue and chroma, but what about value? It would be easier to make this color mixing thing work if there were only two parameters to worry about, and many color mixing books kind of pretend that’s the case. When I talked in my last post about getting the value right when mixing, I suggested that the first thing you do when trying to make any particular color was to first mix the colors you are working with to the correct value. You can then mix them together and get the hue and value you are looking for—because the paints are already at the correct value, you don't have to think about that factor any more, greatly simplifying the problem you're trying to solve. Mixing value first usually works, except when you can't get the right chroma and value because the white paint is pulling the chroma down too far. I’ll talk about strategies for dealing with that problem when I discuss chroma in the next post. Under most circumstances, the “mix the value first” rule makes color mixing much easier to control.

Warmth and coolth

The idea of warm and cool colors has many implications for composition that don’t belong in a discussion of color mixing. Warm colors are generally thought to include red, yellow red, and yellow, while cool colors are thought to include blue green, blue, and purple blue. (I’m using Munsell hue terminology here.) In between colors include green, green yellow, purple, and red purple (some people would label green and purple as warm and green yellow and red purple as cool). There are some aspects of the warm/cool division that are useful to include in a discussion of color mixing.

If you reduce the chroma of a warm color, it appears less warm (raw umber is less warm than cadmium orange); if you reduce the chroma of a cool color, it appears less cool. The most chromatic warm colors are much higher in chroma than the most chromatic cool colors. Compare, for example, cadmium yellow light (a high chroma yellow) and pthalo blue (a high chroma blue). The yellow is much higher in chroma than the blue. Not only that, the yellow is also much lighter in value than the blue. Warm pigments can be very light (high in value) at high chromas. Cool pigments are much darker at their highest chroma. Adding a lot of white to a cool pigment, to bring the value up near to that of cadmium yellow, decreases the chroma still further. You can’t have a high chroma, high value cool color—the physics of light don’t allow it. These kinds of differences are why the Munsell color space is shaped like a bumpy, irregular cylinder.

Because of this effect, high chroma warm colors have more overall punch than high chroma cool colors. Many art books tell you that warm colors advance and cool colors recede. That’s wrong, although it has a germ of truth. The eye looks for contrast. In most paintings, chromatic colors have more contrast with their surroundings. Higher value colors also have more contrast. Because warm colors are more chromatic and higher in value, they have more contrast, so they jump forward. If you drop the chroma and value of warm pigments to match those of cool pigments, they become brownish and don’t have any extra punch at all.

The warm/cool contrast can also be useful when you're trying to figure out what hue something has. It can be easier to ask whether a hue is warmer or cooler than a color near it than to try to figure out its hue directly. Any hue can be shifted either clockwise or counter clockwise on the hue circle. You can think of this as shifting warmer or shifting cooler. For example, a yellow can shift toward green (cooler) or toward red (warmer). That is not to say that red is warmer than yellow (different people have different opinions on that issue), but that shifting toward red is shifting away from a cooler color (green is definitely cooler than red), so it’s useful to think of that as “warmer” in this context. Similarly, a purple can be shifted toward red (warm) or toward blue (cool). As you are painting, you can think in terms of these comparisons. Is the hue on the light side of an object warmer or cooler than the hue on the shadow side? That comparison is an easier task than determining the absolute hue of the light side.

Heraldic contrast

Traditional European heraldry (coats of arms) has a lot of rules regarding how designs can be constructed. One of the fundamental rules is this: no metal on metal or color on color. There are two metals: gold (represented as yellow) and silver (represented as white). All the other hues that can be used are "colors." The rule is that colors can't be placed next to other colors, only metals. Metals can't be placed next to other metals, only colors.

This may seem like an antiquated piece of trivia, useful only to those who are desperate to be the fifth cousin twice removed of the Duke of Cornwall or somesuch, until you look at street signs. In the U.S. (and those parts of Europe and Canada I've visited) almost all street signs follow the heraldic metal on color and color on metal rule. A U.S. stop sign is a metal (white/argent) on a color (red/gules). Highway direction signs also (white/argent on green/vert). Speed limit signs? Black/sable on white/argent. Those few signs that don't follow the heraldic convention, such as construction signs with black text on an orange field, are much less noticeable than the vast majority that do.

What's going on here? Heraldry was originally designed so that painted shields and banners would be clearly visible at a great distance on the battlefield. For that to happen, you need to have a lot of contrast. As it turns out, with the pigments they had available, white and yellow had the best contrast against the other pigments. Thus the avoidance of color contrasted against color or metal contrasted against metal. Even with modern pigments and special reflective surface treatments, the rule pretty much holds up, so sign designers follow it even if they don't know where it came from. Next time you're on the road, try to find signs that break this rule. If you do find one, note that the contrast is poor compared to signs that follow the rule. Same with signs on buildings.

This rule can be useful when you are designing a color scheme and want to highlight a focal area of a painting. If you follow this old heraldic rule, you will have all the contrast you could need.

Battle scenes

are uncommon in Renaissance panel painting. Here is one exception, part of a series of three huge panels, done mostly in egg tempera, commemorating a minor Italian battle (the Battle of San Romano) by Paolo Uccelo. This one is in the National Gallery in London. I've seen it's sister painting in the Louvre. One impressive aspect is the gilding. All of the armor is done in silver leaf, punched and scribed with three dimensional patterns of mail and plate, then glazed with thin layers of asphaltum ground in oil. Very impressive.

Brendan

is seven weeks old.

Practical Color Mixing 1: Value

OK, let's recap. In my first post on color, I concluded that the standard three-primary color wheel is not useful for learning about using and mixing color. In the second post, I briefly reviewed the Munsell color system as a means for describing color and for identifying visual compliments. In the third post, I talked about the difficulty of developing a simple system that could adequately provide a method for artists to mix color.

What we're left with is coming up with color-mixing strategies that can allow a painter to get the job done without too much frustration. Unfortunately, this is complicated stuff, with lots of exceptions and special considerations. It doesn’t make as neat and easily-explained an idea as a simple color wheel. There’s just kind of a lot of stuff that’s important (or at least useful) to know about. And because all of the stuff interrelates, it’s hard to split it up into easily-digestible topics. But that’s what I’ll try to do. In this post, I’ll discuss value. Later, I’ll talk about controlling hue and chroma. Of course, since they are so closely interrelated, in each discussion of one of the three components I’ll also have to talk about the other two.

GETTING THE VALUE RIGHT

If you’re having trouble mixing a color with exactly the right hue, chroma, and value, concentrate on at least getting the value right. The brain weighs value far more strongly than it does hue and chroma. There are any number of paintings out there with wierd hues and no consistent use of chroma, but they work because the values work. (That’s not to say that hue and chroma aren’t important—they are—but to emphasize that value is the most important of the three for a beginning or intermediate painter to concentrate on.)

Value should be considered at two levels in realist painting. First, you need to consider the value structure of the painting as a whole. Do you want most of the painting to be light (a high key painting), most of it to be dark (a low key painting), or for there to be some kind of balance across a wide value rang (a full key painting). What is the range from darkest dark to lightest light? It’s useful to establish that range early, because every object will be rendered in relation to that key.

Overall Value Range

As you think about this, you need to be aware that the value range of paint has only a small portion of the value range of human vision. Consider a painting of a sunset. That sun is much, much brighter than your highest-value white (which you’ll need to tone down in order to get the right hue and chroma). In order to give an impression of that brightness, you will need to make the rest of the scene quite a bit darker than you otherwise might. You are choosing a value scheme that represents the value relationships most important to the composition. That means that you won’t be able to have much contrast in the darks, because their value range is compressed in order to emphasize that very strong light.

On the dark side as well, the blackest black on your palette reflects a lot more light than a really dark shadow does. So there are times when you need to compress the lights in order to show a full range of contrasts in the shadows. Of the painting media, by the way, oil paint has the widest value range, particularly in terms of really dark darks. So it's easier to create believable three-dimensional form with oil paint, and that's one reason why it's so popular.

Therefore, in making decisions about the key of a painting, you need to accept that you are necessarily working with a limited value range, and you need to make intelligent choices about how you use it. There is no such thing as “paint what you see” in this calculation. Artists often manipulate the value range to achieve a specific effect. Rembrandt and Carravagio, for example, both painted low key paintings. But more than that, they made the darks very, very dark, the midtones quite dark, and the lights very light. That creates a marvelous dramatic effect, but there’s nothing realistic about it. It is worth looking at a lot of paintings and thinking about what choices the artists made regarding value range, because those are the same choices youre going to have to make every time you paint. Trying to go for a middle road, in which the lights are fairly light, the midtones are fairly medium, and the darks are fairly dark, is not always the best choice, because it isn’t very interesting and because it’s often not the right way to represent the emotional content of the scene. Don’t think that hue and chroma are the primary determinents of the way your painting feels, because often the real money is where the value is.

Light and Shadow

Within the overall value scheme of your painting, you’ll need to consider value as you work on each object or passage. Often, it’s good to think in terms of two, three, or (maximum) four values in the mass areas each object depicted. On the Munsell value scale from 0 to 10, for example, you might paint the shadow side of a house at value 3 and the light side at value 4. A head might be represented at value 5.5 in the upper lights, value 5 in the darker lights (sometimes called the “halftones”), value 3.5 around the terminator (the shadow edge), and value 4.5 in the reflected lights. You could mix these tones on your palette before you start, lay them down in the appropriate areas, then blend as desired. You could then add highlights at value 6.5 and dark accents at value 3. Doing it in such a pre-planned way can be much easier than figuring it out as you go.

To get these values right, it’s much easier to think about relationships than it is to think about matching the actual value of the object you’re trying to paint. So if the overall key of your painting sets the value of the light side of a cube at value 7, the thing to do is to observe and think about how much darker the shadow side of that cube is. What value in paint best reflects the value relationship you are observing in real life? Is it a 5? 4.5? It takes a lot of practice to get these kinds of relationships right across an object, and then to keep those relationships right across many objects in a single painting (many beginner paintings seem to be keyed differently in different parts of the picture).

One useful exercise is to do a series of paintings in a single hue. If you do it in shades of grey, it is called a grissaile (pronounced gree-zai). A 50/50 mixture of black and raw umber is a good base tone for a grissaile that you can mix with different amounts of white to get the desired value. Doing a series of grissaile studies can help develop your ability to judge and paint value. For each stroke of paint you put down, think about whether it should be darker or lighter than the paint surrounding it, and by how much. Over time, you’ll achieve a much greater sensitivity to value.

One of the typical mistakes that beginners make is to focus on hue and chroma at the expense of value. They might be trying to paint a figure, for example, and mix up some “flesh tone” (or they might have a tube labelled “flesh”). They proceed to paint the whole figure that color, then timidly throw in a slightly darker tone for shadows and edges. The figure looks flat and unconvincing. If you are going to concentrate on a particular subject, and you want it to look dimensional, you need a fairly wide value range within that subject. If that means compressing the lights or darks so that background elements have less contrast, that’s OK. If you’re painting a figure, the shadows on that figure should be a significantly darker than the lights. It is only with a wide dynamic range that you can create the illusion of three dimensional form. I remember when I was first taking painting classes, my teacher would look at my figures, sit down with my palette, and make the darks a good two value steps darker than I had made them (and I thought they were pretty dark). It was a painful experience, but it showed me how to create a successful illusion of form.

White and Black

So how do you make paint darker or lighter? You can, of course, simply add black to darken and white to lighten. If you’re only concerned with value, that will always work. But both of those colors will, under many circumstances, distort hue and chroma.

White, of course, is a critical mixing color; it is the dominant pigment in many paintings. As you add white, however, the color tends to drop in chroma and will often shift hue. Hue shifting isn't too hard to deal with; you can add a touch of a warm or cool color (usually warm) to correct the hue. Dulled chroma is harder to fix (that's one reason why white paint isn't used in traditional watercolor technique). One strategy is to avoid titanium white when you don’t need a really bright opaque white. Both flake white and zinc white are less overpowering and have less tendency to kill the chroma in mixing. Zinc, especially, is good for this purpose. Another strategy is to use glazing, rather than mixing, to adjust hue and chroma. But it is the case that some high-chroma colors are very hard to approximate with paint. So when you are deciding on a value scheme for your painting, one important consideration is whether you will need to showcase any very high chroma colors. If that is the case, you may need to adjust the key of the painting so that those intense colors are the right value without having to lighten or darken them much. So, for example, you might use a higher-chroma, slightly less bright light and it will read as very bright in contrast to the relatively darker, duller colors elsewhere.

I think of black as being one of the less important colors on my palette. Some painters never use it, claiming that is is a deadening color, that there is no black in nature, and that excessive use of it makes your painting look like it has a hole in it. That’s hogwash. Take a look at paintings by guys like Leonardo da Vinci, Diego Velazquez, or Carravagio. They relied heavily on black. Can you really say that their paintings would have been vastly better if they had only known that some modern painters think black makes a painting look damaged? “That Leonardo guy, if only he’d known to avoid black, he might have made a name for himself!” Yeah, right. And don't think they didn't know how to darken colors without black, because they certainly did. They chose to use black because it was the color that worked best for what they were trying to accomplish.

That being said, it is certainly true that mixing a color with black will reduce chroma, and that black is best used with care. Sometimes, strong chroma reduction is exactly the effect you are looking for, so that’s when to use black. Black also causes color shifts. Mix black with a bright yellow (such as cadmium yellow light). Do you get dark yellow? No, you get an olive green (which can be quite useful). Under many circumstances, black acts like a very, very dark blue. Black is often best used the way it was usually used in the 15th century, to darken (and reduce the chroma of) earth colors and other low-chroma colors. I don’t usually use black as a dark dark; instead I tend to make a really dark mixture (such as ultramarine and burnt sienna or viridian and pyrol ruby) and use that. In part, that’s because in oil paint pure black takes a long time to dry and is a relatively “fat” color. But it’s also because pure black is a bit dead compared to mixtures.

Controlling Value

So, if we need to be careful with white for lightening and if black is of limited use in making colors darker, how do we manage value? Carefully.

Take a look at a color wheel, particularly the colors on the outside of the wheel (the highest chroma pigments in each hue). You’ll notice that warm colors. like yellow, are quite high in value. By contrast, cool colors like purple are relatively dark. So your value mixing strategy will need to depend, to some degree, on what part of the color wheel you’re working with.

For example, how do you make a dark yellow? Do you look on the other side of the color wheel, find that a violet is the compliment of yellow, and mix that in? That doesn’t work very well, because many warm colors don’t have a true mixing compliment (they don’t mix to a neutral grey). So violet added to yellow produces a severe color shift away from the yellow hue. Fortunately, there are dark yellows already available—browns are basically dark yellows. So, as artists have been doing for many centuries, you don’t try to mix a dark yellow. If you want to depict a gradation from a light yellow to a dark yellow, you blend in a series of brown colors: cadmium yellow to yellow ochre to raw sienna to burnt umber, for example. Of course, if you don’t like earth colors, it’s perfectly possible to mix similar ones. Some artists like to use a very limited palette of only cyan, magenta, and yellow; with those and white, you can mix colors very similar to yellow ochre, raw sienna, and burnt umber. Personally, I find it much easier to simply use the earths.

How do you make a dark purple? Easy. Purple pigments are already dark, so all you have to do is adjust the chroma (if needed). If you need it even darker, you can mix it with dark transparent colors that are near to it on the color wheel (a transparent dark blue like Prussian blue and a transparent dark red like pyrol ruby, for example). You could even add a touch of black. How do you make a light purple? You’re probably going to have to use some white. If you need a light, high-chroma purple, you may have some trouble, because the white is going to knock the chroma down. So you may need to start with the highest-chroma purple you can find (such as dioxazine violet), so the final result remains relatively chromatic. As noted earlier, you might also want to use zinc, or a zinc-flake mix (a big glob of zinc by itself dries a bit brittle and that can affect the stability of the paint film). If you need a light, low-chroma purple, on the other hand, then mixing with white, then making slight adjustments to hue by mixing in small amounts of other colors, will probably work just fine.

It is also the case that, for many cooler colors like blues and violets, mixing with a small amount of white will increase the chroma. For example, in oil paint, ultramarine blue with a bit of white added is more chromatic than plain ultramarine. But adding a lot of white decreases the chroma. Warmer colors are tend to be at their maximum chroma straight out of the tube.

The easiest overall mixing situation is when you are trying to reduce chroma at the same time you are adjusting value. If the color has a mixing compliment, then, typically, that color will reduce value and chroma at the same time.

Mix the Value First

When mixing two colors, it’s often a good strategy to first get both of those colors to the intended final value. Then, when you mix them together, it’s much easier to judge hue and chroma. If you have a clear idea of what colors you’ll be working with in a painting session, it can be useful to mix up a series of paint strings. One string is a single hue/chroma along a series of values. So, for example, a useful flesh tone is a neutral mixture of cadmium green and cadmium red. You might create that neutral brownish color on your palette, then mix in different amounts of white to make a series of gradations from very light brown to the base cad green/cad red mixture. You could then make darker tones along the same string by adding different amounts of raw umber. Now you have a string of one hue and chroma, but different values. Another string might be based on yellow ochre as a base tone, mixed with different amounts of white to make lighter tones and different amounts of raw sienna and burnt umber for darker tones. As you paint, if you need a hue that is in between the two strings, it’s easy to mix paint from each string at the same value to get the right hue.

Working with a set of pre-mixed values is called a set palette. Some artists take it to extremes, always mixing up a pre-set group of value strings before staring to paint. If you do this habitually, it helps to mix a lot of each paint value in advance and put them into tubes—that way, you don’t spend half of each painting session mixing strings of paint. I don’t do that, but I do typically mix two or three strings at the beginning of a painting session and work from them. You can buy sets of pre-mixed neutral greys at different values from several companies; the greyscale set from Studio Products even comes graded according to Munsell values. I’ll come back to the usefulness of neutral greys later on when I talk about managing chroma.

Madonna with the Child and Two Angels

by Fra Fillipo Lippi, tempera on panel, 95 x 62 cm (37 x 24" ). This gorgeous and delicate painting was done in 1465. Lippi was an interesting character, a Friar who had an affair with a nun. They were both allowed to resign from their respective orders. She bore him a son (Fillipino, who also became a painter) and a daughter (who was not artistically inclined, so far as I am aware).

For all that, his style is beautiful and, I think, possessed of a profound sense of the divine. He probably taught the more famous Sandro Botticelli, whose style is clearly influenced by him.

A hottie

This painting of a lovely lady is attributed to Raffaello Sanzio (Raphael). La Fornarina, oil on panel, 1518-19.

The style of this painting is not as delicate as much of Raphael's other work. For that reason, there is speculation that this painting might have been done by a follower of Raphael, or perhaps it is a copy by a skilled assistant in his workshop of a lost original.

She's a babe nonetheless.

Glazing

Among oil painters, there seems to be a common misconception that glazing is some kind of mystical technique that only a few can master. The basic process is, however, very simple. Glazing is putting one layer of paint over another so that you can see the underlayer through the upper layer of paint. Glazing is a form of indirect painting, which just means that you are painting with more than one layer, allowing previous layers to dry before you add more paint on top.

Glazing can be used for a number of purposes. As I noted my post comparing the glazing methods of Italian and Netherlandish Renaissance painters, glazing can be used to create optical color mixtures (a blue glazed over a yellow makes a green) or to create modeling effects (thicker layers of transparent paint are darker, so you can adjust value by adjusting the thickness of the paint). Some artists glaze over a whole painting to unify the overall tone. Others will glaze specific parts of the painting. One method is to do an initial monotone underpainting (in shades of grey, for example) then apply color over it. This simplifies the process of painting by first tackling pure value, then working out color. Some modern portrait painters will do an initial painting of flesh in shades of green (they incorrectly call this a "verdaccio"). They then glaze with reds and oranges (complimentaries and near-complimentaries to green), providing the flesh tones with a sense of vitality that is difficult to achieve with direct painting. Glazing can also be useful for maintaining chroma in light colors. Mixing with a lot of white will seriously reduce the chroma of most colors, resulting in a look often described as "chalky." If you glaze the same color over white, however, you can achieve an optical effect that is high in value, with more chroma that you could get by mixing that color with white.

Because a glaze darkens what it covers (unless its a scumble—see below), it is best to do the underpainting lighter than the intended final effect. If you are going to glaze, it's important for the underpainting to have as smooth a surface as possible. That's because irregularities will trap excess amounts of paint in the glaze layer, creating wierd little spots of darker paint. So, before the paint dries, it's a good idea to go over it very lightly with a soft dry brush, looking for lumps and gently brushing them down. After the underpainting has dried thoroughly, you may want to wet sand to create as smooth a surface as possible.

In selecting paint colors to glaze with, it is useful to distinguish among opaque colors (like cadmium yellow), semi-transparent colors (like ultramarine blue), and transparent colors (like alizarin crimson). While any of these colors can be used for glazing, transparent and semi-transparent colors are darker when they are put on more thickly. Opaque colors can be used for glazing, but only when they are applied in a thin layer. A thick layer of an opaque color is not a glaze, because you can't see the underpainting through it.

Many oil painters think that the best way to glaze is to dilute the paint with an oil-resin medium to a watery or syrupy consistency (this is what a lot of art instruction manuals tell you to do). The paint becomes less opaque because the pigment particles are separated by a larger than normal amount of transparent vehicle. This type of glaze is called a dilution glaze. In my (deeply humble) opinion, it's the wrong way to glaze. It's bad technique for (at least) three reasons: (1) all of that extra resin and oil will darken and yellow over time, ruining the effect; (2) dilution glazes tend to create a sort of "tinted photograph" effect that doesn't have the solidity a painter is usually trying to depict; and (3) the documentation I've found on historical glazing techniques suggests that only small amounts of resin are detected in glazing layers in Renaissance Netherlandish paintings, which I consider to be the gold standard in glazing for both beauty and longevity.

A better method is called a reduction glaze. This approach involves adjusting the transparency of the paint by adjusting the thickness of the paint layer. While you can do a reduction glaze with nothing but pure oil paint, it helps to first lubricate the surface by applying a very thin layer of a slippery medium. My preferred glazing medium is a 50/50 mixture of black oil (linseed cooked with lead) and Venice turpentine (if you don't like to use substances containing lead, linseed oil will work almost as well). Studio Products also sells an excellent glazing medium. Put a drop of medium on the surface, rubbing it in with your fingers to spread it as far as possible. This way, you can cover a large area with just a few drops of medium. In addition to putting some on the surface, you can also put just a tiny bit of medium in your paint, but I don't usually find that necessary.

Mix up the color you want to glaze with. Apply it thickly and evenly to the desired area with a brush. It will look like a horribe mess at this stage. You will now reduce the thickness of the glaze to the desired opacity and value. Do this by dabbing with a soft brush, smearing with your fingers, rubbing with a cloth or sponge, or whatever works to adjust the glaze to achieve the desired effect. With a little practice, a reduction glaze is really pretty easy. You can get nice gradations in color and value by creating a gradation from thin to thick. Or you can create gradations from one color to another. Once you have the glaze spread to the right thickness, you can, if you like, paint into it with other colors. For example, you can apply light highlights into a wet glaze and then blend it in. If desired, you can let your glaze dry and then add one or more additional layers of glazing. For example, you can get really intense, chromatic darks by glazing with multiple layers of transparent paint.

When mixing colors for a glaze, it is sometimes helpful to add a small amount of white to your mixtures. This provides a greater sense of solidity. If you glaze with very light colors containing a lot of white, it is usually called a scumble. Titanium white, being very opaque, can be a bad choice for scumbling. Flake white and zinc white are much easier to create transparency effects with. A very white, hazy glaze is called a velatura ("veil"). A velatura can be a great way to depict transparent smoke, haze, or fog.

Sorry for the low frequency of posts lately

I've been busy helping to take care of my six week old son, and I've had a hard drive crash. I also try to paint from time to time. I am still working on the series on color mixing, and I'm trying to recover a long post I had almost ready on the subject.

I'd like to note that I've had more than 2,000 visits since I started the blog at the end of June. That's not much for sites like boing boing, which probably has more hits than that in a typical hour, but it seems pretty good for a personal site that restricts itself to a fairly obscure topic. Thanks for stopping by, and please feel free to leave comments.

I'll try to get back into the swing of things this week.

Bottle of oil and blue glass

Awhile ago I posted on a little sheet of copper I had prepared for painting on. Here's what's on it now. Oil on copper, 5 x 7". It's not done yet—I need to correct a couple of elipses and clarify some of the details. But so far I like it.

The copper takes oil paint like nothing else I've worked on. Normally, any surface is either absorbent or slick. Either way, the initial application of oil paint can be a bit of struggle. Not copper. The paint flows right off the brush, with no streakiness, chattering, staining, or other problems. Also, you can incorporate the tone of the copper itself into the painting. I need to find a source for bigger sheets of thin copper to paint on.

Renaissance layering

When you walk down a museum hall full of Renaissance paintings, you can easily pick out the Italian paintings from the Netherlandish paintings at a glance. While the subject matter is similar (mostly scenes from the New Testament), and the pigments are basically the same, they used color in completely different ways. I've come to realize that the difference largely comes down to how layering was done.

By layering, I mean variations on glazing. I am using that term broadly to mean any application of two or more layers in which the layers beneath contribute to the final visual effect. Glazing can be done with relatively transparent colors such as red lake, or with opaque colors such as vermillion (if it is applied thinly enough). In both the Netherlandish and Italian traditions, glazing was critical to the final appearance of important parts of almost all paintings, but the way they used glazing was different.

In Netherlandish painting, glazing was used to adjust values with minimal loss of chroma. Typically, an opaque color, such as vermillion, was applied first. The initial layer was typically flat—i.e., with no attempt to model the forms. Then a transparent pigment of similar hue, such as red lake, was applied over the initial flat layer. The transparent color was applied thinly in light areas and thickly in dark areas. Often multiple layers were applied to darks. Because thicker layers of transparent pigments absorb more light than thin layers, a thick layer is darker than a thin layer. This approach to modeling, in which darks are created not with darker colors, but with thicker, light-absorbing layers, creates an optical effect that is completely different than simply mixing a light, a midtone, a dark, and then blending them. Blacks and other dark, dull colors were avoided in Netherlandish glazing. Fully-modeled objects have a jewel-like tonality that jumps off the picture. This glazing technique wasn't used throughout the painting, but was carefully applied in order to control the structure of the composition. It was not used in modeling flesh tones, which were typically done very thinly, in one or two layers.

In Italian painting, by contrast, glazing is used to generate hues through optical mixing of layers. For example, in early Renaissance Italian tempera painting, flesh tones are created by first applying a layer of dull green, then modeling in a dark dull brownish green. On top of that, the flesh color is created by applying an opaque pink (flake white mixed with vermillion) thinly enough that the underpainting shows through. Later in the Renaissance, when Netherlandish oil paintings began to be imported, the Italians tried to copy those effects in oil paint. But while they knew how to make oil paint, they didn't know about Netherlandish layering. They created darks by mixing dark dull colors, including black. Italian oil paintings from that period show none of the chroma intensity in the darks that make Netherlandish paintings so special. It wasn't that they were stupid; it was that they thought about color and layering in a different way, and that approach created a different set of effects. The Italian method was also useful. Botticelli, for example, underpainted foliage with black before glazing over with greens. This makes the foliage fade into the background. He underpainted flesh with yellow ochre, to make flesh tones that had a warm cast. Michelangelo used a traditional (and then somewhat old-fashioned) underpainting with greeen earths for flesh tones. If he wanted two different tones of blue drapery in a painting, he would underpaint one with black, then ultramarine mixed with varying amounts of white and black. The other would be done in the same set of ultramarine gradations over white gesso, creating two completely different ranges of blue with the same surface pigment. Leonardo's sfumato method involved a very dark underpainting in dull earth tones, followed by glazing with light colors mixed with a lot of white. Italian painting is generally brighter and more chromatic than Netherlandish painting, but the darks are more dull. The eye picks up on these differences very easily.

It's useful to understand how both of these kinds of layering effects are accomplished, because if you know how to do both, you have a broad range of useful tricks.

Another Ireland photo.

How to get oil paint to dry quickly

The joy and the curse of oil paint is how long it takes to dry. It's great to have lots of time to work with the paint, re-do mistakes, and get those gradients and edges just right. But then, in multi-layered painting, there are times where you just need to stop and let the paint dry. For days. It can be very disruptive to artistic momentum.

Some painters are fine with letting paintings dry for days or even weeks. They work on more than one piece at a time and come back to each one when it's ready. But sometimes you want stay with one piece, working every day. Here are some ways to control the rate at which oil paintings dry:

1. Paint in thin layers (like the thickness of a normal coat of house paint).

2. Avoid slow-drying pigments like titanium white and ivory black. Use fast-drying pigments like lead white and burnt umber.

3. Avoid paints made with slow-drying oils like safflower and poppy. Also avoid walnut oil, which dries faster than safflower or poppy, but slower than linseed.

4. Use a lean lead-containing medium such as Maroger's.

5. Add a bit of turps to the first layer. Turps doesn't make paint dry faster, but it makes the paint layer thinner, which does make paint dry faster. Don't add so much turps to paint that it becomes washy or watery. Just add a little bit.

6. Paint on a panel primed with glue-chalk gesso. The first layer will have some oil absorbed by the gesso, so the paint dries more quickly.

7. Add small amounts of metallic driers to the paint. I prefer lead napthenate. I add one tiny drop (from a toothpick) per blob of paint on the palette and mix thoroughly. Excessive use of driers will damage the paint film, but that much should not be any problem. I generally add driers only to slow-drying pigments.

Some painters also use alkyd mediums such as Liquin, Neo-Meglip, and Galkyd. I don't use alkyd mediums and I don't recommend them. However, they do make oil paint dry faster.

When I need to, I can get oil paint dry in a day, so I don't usually have to wait for a layer to dry before I can paint over it. Sometimes, I choose to use a medium that makes the paint dry more slowly, or I use a slow-drying pigment like titanium white. But when I do that, I know that the paint will need extra time to dry. My glazing medium (a 50/50 mixture of black oil and Venice turpentine) is somewhat slow-drying, so glazes usually take two or three days to dry.

It's also the case that I often complete one section of a painting at a time. That way, it doesn't matter whether yesterday's paint is dry, because today I'm working on a different part of the picture.

Online workshop: Renaissance Italian painting

I'm doing an online workshop over at the Wetcanvas forum on Renaissance Italian painting materials and methods. You can follow along here.

Jacob Collins

is one of the great modern realist painters. He's a student of Ted Seth Jacobs, who also taught Dennis Cheaney, who I've studied with. What I particularly like about Jacob is his facility in finding exactly the right combinations of light and color to create a mood. The work is finely-rendered without being fussy. It is informed by the work of the past, but is still clearly from the early 21st century. In his best work he creates a kind of visual hyper-reality, in a manner similar to, but different from, the work of Andrew Wyeth.

You can see his work at his web site. There's some other good stuff at the Art Renewal Center.

I hope he doesn't mind my posting a sample of his work:

Pigments, paints, and color mixing wheels

This is the third in a series of posts about color for painters. In the first, I established (to my satisfaction, anyway) that the usual advice on color that you see in most books on painting, based on a three primary color wheel, is not very useful. In the second, I described the Munsell color system, which provides a useful approach to describing color, although it doesn't say a lot about how to mix pigments together.

I know that you've all been waiting with great anticipation for this next post in the series, in which I reveal a simple and comprehensive method that allows you to easily mix exactly the color you want with just a few inexpensive tubes of paint. Alas, I must now confess to you that—so far as I know—such a system doesn't exist. What I can do is to describe some of the issues involved in the complex subject of color mixing and then present several ways to approach the problem.

First, let’s talk a little about paint and pigments. Pigments are colored powders. Some of them are rocks and dirt that have been ground up and purified, some are simple chemical compounds, some are created via complex modern organic chemistry, and some are tiny water-soluble particles that are made suitable for painting by attaching them to larger uncolored particles. Each pigment has a characteristic color (hue, chroma, value) which is the result of the pigment particles absorbing some wavelengths of light and reflecting others. Changing the particle size often changes the color, sometimes radically. Heating many pigments will change the color—burnt sienna is just a cooked version of raw sienna. Changing the medium in which the particle is suspended often changes the color due to a different refraction index—ultramarine blue is much darker in oil paint than in egg tempera. Some pigments come from a single pigment company and in that case all paint makers start with the same raw material. Other pigments are available from multiple suppliers and each may provide a version that is subtly, or not so subtly, different—there are many, many variations on cadmium red. The color of most pigments is different when they are laid on thick (this is called the masstone) and when they are laid on in a thin layer (this is called the undertone). Pigments are usually described as “opaque,” “semi-transparent,” or “transparent.” That refers to how well light passes through the pigment when it is mixed into a transparent binding vehicle. Transparent pigments are much darker and lower in chroma when they are thickly applied than when they are thinly applied. Pthalo blue is a very bright color when spread thinly, but a dark, almost black, blue when it is very thick. Opaque colors are more likely to have a masstone and undertone that are basically the same, although there are exceptions. Transparency varies somewhat from one painting medium to another, because it is a function of the refractive indexes of the pigment and the binding vehicle. With water media, the refractive index of the vehicle changes as it dries, so what looks transparent when you lay it on may be fairly opaque when the paint dries.

Almost no pigments are manufactured for artist’s use; they are made for large-scale industrial purposes, such as signs, cars, house paint, printing, cosmetics, and all of the other industries that use these materials in far greater quantities than artists do. Paint manufacturers buy these pigments and grind them with a binding vehicle and other components to make paint. (In some cases, individual painters may purchase powdered pigments and make their own paint.) A tube of paint may contain only one pigment or several; if adulterating pigments are present in small amounts, it may be considered legitimate not to note that on the packaging. Many paints are mixtures of pigments to make a certain color not obtainable with just one pigment—many companies sell a paint mixture they call “flesh,” for example (usually this means some sort of pinkish attempt at caucasian skin tones). Some companies sell mixtures that are designed to mimic an expensive pigment. So a paint called “cadmium red hue” won’t contain any of the expensive cadmium red pigment, but instead will have a combination of other pigments designed to have similar color characteristics.

So, given these issues, it’s impossible to just develop a simple model of color mixing; every artist uses different pigments, in different media, made differently by each company (and, perhaps, formulated differently from one batch to another). And every artist applies paint differently.

Even if you could correct for all of these factors, there are other challenges. Let’s look at one attempt to produce a color mixing system for artists: the Quiller wheel. Stephen Quiller, a working artist (mostly in watercolor and acrylic) has designed a color wheel to assist artists in figuring out how to mix color. A large number of common colors are placed in various positions around the wheel. Where the color is placed depends on (1) the color’s hue and chroma; and (2) the color’s mixing complement (which is directly across on the other side of the wheel). Color placements are a matter of Mr. Quller’s judgment and extensive mixing experience, not any sort of mechanical measurement. Lower chroma colors are closer to the center of the wheel, while higher chroma colors are closer to the outside. So if you are using the Quiller wheel, and you want to mix a particular color, you would find the location on the wheel of the color you want to mix, then mentally draw a straight line between two actual colors. In theory, any color on that line can be mixed with those two colors. You can therefore find a mixture that is the one you want.



A color mixing wheel such as this will often get you into the right ball park when mixing colors. Unfortunately, it has some problems. First, there are the issues of paint variability discussed above. One cadmium red light is not necessarily the same as another. Second, there is the problem of hue shifts. Because of the physical properties of pigment, when two colors of paint are mixed in different proportions, the hue doesn’t always follow a straight line that can be plotted on a wheel. The hue instead follows a curved path that is not predictable just from knowing the colors of the two paints being mixed. This curved path might mean that the color you want cannot be mixed from the two colors you’ve selected, even though it looks like that should be possible from looking at the color wheel. Another problem with a mixing color wheel is this: paints can have multiple mixing compliments. A complimentary mixing pair, you will recall, is two paints that, in some ratio, can be mixed to form a grey color with 0 chroma (or very, very close to 0). A mixing color wheel attempts to place complimentary pairs directly opposite each other on the wheel. But because in real life a pigment may have more than one mixing compliment, its actual location on the wheel is an arbitrary choice. Since the wheel is trying to do two things that are not always compatible (show the appropriate location for mixing and show complimentary pairs), it represents a compromise. It's a set of guesses designed to help the artist get close to what he or she is looking for. It’s not a scientific instrument; it’s a compendium of rules of thumb, and those rules of thumb are often wrong. Another problem is that the wheel shows purples and yellows at opposite sides of the wheel, indicating that they are complimentary mixing pairs. But the reality is that most yellows and most purples don't have a mixing compliment, so the wheel deceives you when you try to mix those colors together.

There’s another problem with mixing wheels. They help you get into the right ballpark with the hue you are looking for. They can also give you an idea of what chroma any given mixture will be, since you should be able to find the approximate chroma of a mixture by finding where it lies on a line between two mixing pairs; the closer to the center of the circle, the lower the chroma. But what if you mix the perfect hue, and it’s the right color. How do you get the value you want? If you want a darker color, mixing with black will reduce the chroma drastically and will often shift the hue. If you want a lighter color, mixing with white will also reduce the chroma and will often shift the hue as well. So you may have the perfect mixture, except for value, and still not know how to get the final color you want. The color mixing wheel doesn’t get you to the finish line.

That all being said, the Quiller wheel (or something like it) is a useful tool that can be helpful, especially for beginners, in figuring out the basics of color mixing. There are other mixing wheels out there, sometimes with fancy sliders that you can turn around a cardboard wheel. There is also color mixing software that attempts to do the same thing. They all have significant limitations when it comes to making subtle mixtures of actual paints.

So what’s a poor painter to do?

Well, since many real-world painters manage to get good results with color, it is obviously possible to do so. In the next post, I’ll discuss several strategies for color mixing.

Latest in the "stuff stuck on the wall" series

This is "Wrapping Paper," 16 x 12", oil on panel.

Politics

On the fifth anniversary of the terrible 9/11 attacks, I'd like to simply remember those innocents who died on that awful day.

Since this is a web log, I'd also like to note that I have strong opinions about politics, international relations, history, economics, the nature of freedom, the proper role of government, and other such matters. And I'm not going to say anything about those topics on this site. Please feel free to imagine, if it matters to you, that my beliefs and yours are remarkably similar.

A photo take in Waltham, Massachusetts on the Charles River.

Technorati Profile

I'm having trouble getting Technorati to register that I still post to this blog. According to them, I haven't posted here in weeks. The link above is my attempt to correct this by deleting this web log from their list, then re-register it. The process includes posting the link above. It doesn't seem to have worked. I've followed the instructions on how to do this, and they used to register my posts. Then they just stopped. Anyone have a suggestion?

More on color

In my last post about color, I discussed the inadequacies of the standard color wheel and explained why we're going to have to replace it with two things: (1) a more accurate way to describe color; and (2) a system for approximating real-world paint mixing. In this post, I'll talk about describing color. As I do so, I'll refer you to certain sections of the Handprint web site (from which I have stolen shamelessly) in case you want more detail.

Although we often still see the standard three-primary color wheel in books about painting and color mixing, it really went out of date in the late 19th century, when guys like Ogden Rood demonstrated that it pretty much stinks for describing color accurately. There is nothing in the way humans perceive light to support the idea of three unmixable primary colors (red, yellow, blue), each of which is complimentary to a specific mixable secondary color (red and green, yellow and violet, blue and orange). In fact, it makes sense to me that there are no special primary colors at all, whether the traditional artist's primaries (red, yellow, blue), the printer's primaries (cyan, magenta, yellow), or anything else.

A number of more accurate ways of describing color have been developed. Many of them are designed primarily to support the needs of the print industry, the dye industry, manufacturers of video equipment, and other commercial ventures. They are needlessly complex for our purposes. The best system that is comprehensive enough, but not too complex to be easily understood, is the Munsell color system. It was first developed in the early part of the 20th century and has been updated a few times since then, although the original structure remains. Any such system represents a series of compromises, so there are ways in which Munsell is imperfect, but overall it suits our purposes better than any other that I am aware of.

Rather than a color wheel, Munsell is built around a three-dimensional color space. This space takes the shape of an irregular cylinder. Munsell uses three properties of color: hue, chroma, and value. I described those properties in detail in a previous post.

Running up the center axis of the cylinder is the property of value. At the bottom of the cylinder is value 0 (pure black); at the top is value 10 (pure white). So, for example, a value 6.5 gray is fairly light, while a value 1.0 gray is almost black.

Running around the outside of the cylinder is a hue circle. It is defined by five principal colors (there are no primaries in Munsell). These colors are red (R), yellow (Y), green (G), blue (B), and purple (P). These are generally represented in clockwise order, starting with yellow at the top. The five principle hues have five intermediate hues in between them: yellow red (YR), green yellow (GY), blue green (BG), purple blue (PB), and red purple (RP). Within each of the hues are ten subdivisions, with 5 at the center. So 5BG is a pure blue green, while 2BG is more blue and 9.3BG is more green.

Each of the principal hues has a visual compliment that is the intermediate hue directly across from it on the circle. So the compliment of red is blue green, the compliment of yellow is purple blue, the compliment of green is red purple, the compliment of blue is yellow red, and the compliment of purple is green yellow. These compliments correspond (approximately) to how humans see color. Munsell compliments are reasonably close to actual data on afterimages. If you stare at a spot of green for a long time, and then look at a neutral gray surface, most people who are not color blind report that they see an afterimage within Munsell's red purple range. The same goes for each of the other complimentary pairs on the hue circle. You see these afterimages because of the way that cone cells on the retina work. I'm not going to describe the physiology, but it helps to know that these are real phenomena (which I am oversimplifying drastically here), not arbitrary or aesthetic conventions.

If the value parameter is a line down the center of the cylinder, then the chroma parameter radiates outward from that center line to the edges of the cylinder. Zero chroma (gray/black/white) is at the center. Moving outward are increasingly chromatic (intense) colors. So a value 6 yellow at chroma 1.5 is basically a warm grey (not very chromatic), while a value 6 yellow at chroma 15 is very intense.

There is no arbitrary maximum chroma, so the chroma scale for each hue runs from 0 to however intense that hue can get. As new, brighter pigments are developed, they are simply placed at higher chroma levels than those of older pigments. Any pigment can therefore be placed upon the Munsell color tree. Because of the physics of light and the nature of color vision, the maximum possible chroma is different for different hues. For example, the maximum possible chroma of a light-valued yellow is much higher than that of a light-valued purple. Maximum chroma for a given hue is also different depending on value. So the Munsell color space is a bumpy, uneven cylinder (when Munsell first invented this system, his realization that the color space couldn't be symetrical was a big improvement over previous systems that had tried to cram a messy reality into an idealized circle or triangle).

Colors are named in Munsell in the standard notation of hue value/chroma. So vermillion is noted as 8.5R 5.5/12. That means that, within the hue of red, it is at position 8.5 (closer to yellow red than a pure red), with a value of 5.5 (right in the middle) and a chroma of 12 (fairly intense). Some paint manufacturers, such as Liquitex, put these numbers on every tube of paint. Unfortunately, that's rare.

The Munsell system has been updated several times to make it more technically accurate, but none of those updates is significant for our purposes. You can buy color sets from the Munsell company. They consist of a book describing the system, a bunch of color chips (sets have either glossy chips or matte chips), and pages with little pockets that the color chips fit into. The idea is that you learn the system by fitting each chip into its appropriate pocket. I haven't bought a color study set, not because I'm uninterested but because they cost hundreds of dollars. Getting a set and placing all of the chips would not be a waste of time for a serious student of painting.

That's Munsell. Boy, that was a lot of explanation, even though I picked the simplest useful color system that I know of and avoided extraneous detail. Color is really complicated.

So how is Munsell more useful to a painter than the old three-primary color wheel? First, it dispenses with the confusing idea of primaries and secondaries while more accurately identifying useful complimentary color relationships. These relationships are of great value in choosing harmonious color relationships. Second, as you become more familiar with Munsell, you can begin to think about colors in terms of how they relate to each other within the color space. If you are looking at a blue wall, for example, and you are thinking in Munsell terms, you can figure out where the color lies and how to accurately describe it. What is its hue? How chromatic is it? What value is it? How do those parameters compare to other colors you are trying to work with? How do the hue, chroma, and value of the wall relate to the hue, chroma, and value of the blob of paint you are trying to use to represent it? Some artists pre-mix a set of colors on their palette in Munsell value steps. Several companies sell paints that are graded according to Munsell; Studio products sells a set of neutral grays and another set of greens, all the same hue and chroma, of different Munsell values. These are particularly useful for underpainting.

There isn't much in Munsell that helps you figure out what color you will get if you mix two paints together—that's not what it's for. What it does do is help you decide what color you are trying to get to. And for that, its really excellent.

Lots more on color in future posts.

Tags: painting, color

Update on Robert Doak

I wrote about Robert Doak's oil paints back in July, when I first started this web log. Today, he called me. He had noticed my post here, looked up my phone number on his customer list, and wanted to thank me for recommending his products. He also asked about my statement that some of his paints separate, so that a oil oozes out of the tube when you remove the cap (I've only had this happen with a small percentage of his paint tubes).

He said that he almost never gets this complaint. He wanted me to know that, when it happens, it does so because he uses very little stearate, which is a clear, inexpensive pigment that paint manufacturers use to prevent separation. It also reduces pigment load and (when used in excess) makes paints more thick and difficult to work with. Cheaper brands of oil paint use a lot of stearate, to improve shelf life and reduce the percentage of expensive pigments in their paint (that's part of why student grade paint is usually very stiff). I have never been concerned about separation with Doak's paint, because I know it happens because he emphasizes pigment load and smooth handling over shelf life.

In the original post I said that the way to deal with separation was to squeeze your paint out onto absorbent paper, wait a couple of minutes, then transfer the paint to your palette with a knife. Mr. Doak said doing that over and over might tend to leech the oil out of the paint tube and cause the paint in the tube to harden (I haven't had that happen). He recommended instead storing any tube of paint with separation issues cap downward, so the oil moves back up through the pigment in the tube. I told him I'd try that and pass on the tip.

I still strongly recommend his paint.

Tags: painting, oil painting, painting materials

Miles Mathis

is a curmudgeon, and I mean that in a good way. He’s a modern realist painter who does mostly paintings of women and girls, some nude, some not. I like some of his stuff and find some of it rather saccharine, but then he’s a selling artist and I’m currently just a wannabe.

At his web site, he has a number of essays that express strong, independent opinions about art and culture. He writes well and with great conviction. I certainly don't agree with everything he says, but I find it very worthwhile to check his site from time to time and see if he’s written anything new. What he writes is almost always worth reading and thinking about. He recently posted a short essay on his painting materials and techniques. He’s a traditionalist and—not surprisingly—he's cranky about how most other artists are lazy with choosing their methods and materials. He paints on linen and primes it himself with lead white. He uses mostly an earth palette and believes strongly that those are the colors that can best be used to represent flesh (I often use earths for flesh tones also). He uses a home made dammar final varnish.

Many buyers have said that my paintings have the same sort of paint that old paintings seem to have, whereas contemporary paintings, even when they are very good, don't. There is a very simple reason for that. I work differently than most modern painters, and that difference starts with my canvas. In my opinion almost all modern materials are garbage, pure and simple. They were created for speed and convenience and price and safety, not for quality. Most professional artists know this and will admit it, and yet most professional artists, even at the top of the field, use inferior pre-stretched canvases.

While I agree with much of what he says, I do have a couple of quibbles. I, too, like to prime with lead, but he uses a lead white paint (Old Holland cremnitz white). I'd recommend an actual lead white primer (he may not be aware that those exist on the market), such as Studio Product's excellent white lead in black oil primer or Williamsburg's lead oil ground. He also confuses organic and inorganic pigments. Earth pigments are not organic; they're rocks and dirt. Many modern pigments, such as pthalocyanines, are classed as organic, since they are based on various carbon molecules. He does correctly label the cadmium colors he despises as inorganics. But the gist is clear: he prefers an old master palette (even if he doesn't know how to describe it technically) from before the explosion of modern pigment manufacture in the 1800's. Specifically, he says he likes Titian's palette, although he doesn't say exactly what he means by that. Titian used colors like azurite and lead tin yellow that are pretty hard to find these days (but not impossible). If you like writing that is passionate and interesting, take a look at his site.

Can we talk about color?

Many artists seem to spend some time learning about color, then kind of get lost. It's a tough subject to get your brain around. You see some version of a color wheel, learn a bit about how colors on opposite sides of the wheel (complimentary colors) are supposed to behave, and so on. Then you start to try to mix paints, and you realize that there is a lot of important stuff that conventional color theory doesn't manage very well. It's confusing, and I'm here to tell you that it's not you. Colors shift all over the place when mixed together, in ways that the color wheel doesn't predict. Some colors seem to have two or more mixing compliments. Other colors, that should theoretically be complimentary, don't mix that way. White and black cause colors to become chalky or dull, so how do you make colors darker or lighter? How the exactly does brown fit in? The outside of the color wheel has some light colors and some dark colors—what's with that? Secondary colors don't seem very secondary. How exactly do you make a dark yellow? Do the primaries, secondaries, and compliments reflect some underlying reality of color vision, or is that just an arbitrary convention?

Color theory, as found in most art books and art classes, doesn't actually help a working painter all that much. You may find that whenever you try to mix a specific color, you get "mud." You might cope by just getting a lot of tubes of paint so that you rarely have to do much mixing. Seeking clarity, you might buy a book like "Blue and Yellow Don't Make Green," which promises a new approach to color, but is based on concepts invented in the 1700's. (And written in an irritable, pretentious, finicky style. By a guy who doesn't know how to construct grammatical sentences. But I digress.) Or you find something like the Munsell color system, which does a good job describing color, but doesn't show how to mix those colors after you identify them. Reading books and looking around on the internet gets you a little closer, but mostly, by trial and error, you just figure out what works, using a small subset of available pigments. You memorize some useful mixing recipes. A lot of the time, you muck around with paint until you get something that looks about right.

If you delve more deeply, you find that the subject of color is incredibly complex, because it requires reconcilliation of the physics of light wth the messy, non-linear neuroanatomy of the human retina, optic nerves, and visual cortex. Most of what's written about color is not for painters, and most of what's written for painters is by people who've learned to mix paint, but don't actually understand color that well. One excellent resource is the very fine handprint web site, where the author has done incredible amounts of reading, research, and testing with watercolor paints. But the stuff he has on color goes on and on, and on and on, so it's hard to find the real practical stuff (it's there, and it's worth looking for).

So, while I don't pretend to have a really thorough understanding of color as it pertains to painting, I thought I'd try to boil down what I do think I have a clue about. It's a little easier for me, since when I was in graduate school I did a bunch of work with the psychology of visual perception (I'm even published in the field). I will not, however, subject you to complex equations, the details of opponent process color vision theory, or technical color space specifications that are designed to meet the needs of the print, computer monitor, and motion picture industries (you're welcome). I'll try to stick with what you need to know in order to describe and mix colors.

So, to start out, we need to dump the color wheel. It was a useful innovation back in Isaac Newton's time, but we've moved on since then. The biggest problem with it as a tool for painters is that it's trying to do two different things at the same time, and it does both of them poorly. First, it tries to provide a model of human color vision, including how the eye processes complimentary colors—whatever those are. But when you test how actual vision works, you find that the color wheel is a terrible model of color vision and that much more accurate models have existed for well over a century. Second, it tries to provide a guide to color mixing. It does that very badly as well, because real color mixtures don't fit the standard color wheel model in any coherent way.

It's become apparent to me that we must divide the topic of color for painters into two: (1) a way to describe color as it is found in the natural world and as the eye perceives it; and (2) a way to conceptualize how to mix desired colors using particular combinations of paints. There is no system that does both of those tasks, so let's just dispense with the color wheel and start over with two separate (albeit related) topics. And we'll get to those topics in later posts. I promise.

Tags: painting, color

Three ways to use oil painting mediums

It is certainly possible to work with nothing but plain, unadulterated oil paint, but certain effects are easier to achieve with judicious application of other materials. These can include various mixtures of varnishes, balsams, solvents, and thickened oils; such mixtures are called mediums. Because all mediums weaken the final paint film somewhat, they should be used in very small amounts.

Here are three ways to use mediums:

1. An oily or resinous medium can be mixed directly with paint. If so, it is best to use the smallest amount that will achieve the effect you are looking for—generally no more than 20% of total paint volume, and preferrably much less. Use a knife to mix a bit of medium thoroughly into each blob of paint on your palette, or into whatever mixture you want to have the properties the medium imparts. Then paint normally. A good medium will make the paint handle more smoothly. Artists have various opinions about which mediums are best.

2. An oily or resinous medium can also be spread thinly onto the surface of the painting before applying paint (this is referred to as painting into a “couch” of medium). Wipe with a cloth or rub it in with the palm of your hand to get it as thin as you can. Don’t apply medium to areas where you will not be painting this session, since oil on the surface can eventually result in excessive yellowing. The couch method has the effect of lubricating the surface (which can make precise detail work easier) and reducing “chatter” (i.e., dragging and streaking of paint strokes). It also improves adhesion between layers, especially if the medium contains a balsam.

3. If you use a thin medium containing a high proportion of solvent, keep it in a small covered container next to you as you paint. Dip your brush in medium and mix it into the paint on your palette just before you apply it. Don’t make the paint watery; use just enough medium to make the paint more workable. Solvents can dissolve a lower layer of paint if you haven’t given it time to dry completely. Use solvents only if you have good ventilation and keep the medium container covered when you are not using it in order to limit evaporation.

Now go forth and smear colored goo on flat surfaces!

Tags: painting, oil painting, painting methods, painting mediums