THE COLOR OF SHADOW
The color of light and the color of shadow relate to each other. If the relationship between light and shadow is inappropriate the reality of the scene is marred. Getting shadow color right is often hampered by not understanding the complex light effects that modulate its color.
The academics solved the problem of shadow color in their own way by keeping all shadows uniformly warm. They often painted a very warm underpainting that was preserved in the final painting by semi translucent layers of color over the underpainting. This underpainting was often burnt sienna or a similarly warm, yet neutral hue. If there was any modulation of the shadow color it was by very subtle glazing. This gave a similitude of reality by ensuring that the values were extremely accurate. However, color vibrancy was lost following this formula and often a uniformity of temperature suffused the shadows with chromatic falseness.
The revolutionary idea of the impressionists was that reality was much more complicated and could not be described using the brown paint of the academics. Many painters began to paint in the field using direct observation to guide their color choices. Impressionist paintings immediately began to reflect a more vibrant and colorful reality. These newly discovered methods also allowed the impressionists to pack more observation into their paintings. Instead of brown shadows we began to see purples and blues. But there were even more subtleties to be discovered.
One afternoon I was looking out from a twenty-four story building onto a building below. There had been a recent snow and one of the air-conditioning units on the roof was casting a long shadow. I could clearly see how the shadow was warmer closer to the air-conditioning unit and gradually cooled as the shadow lengthened. For me it adequately explained and demonstrated what impressionists referred to as Monet's envelope. This principle says that objects or spaces that protrude into the blue amorphous envelope of the sky become cooler in color. Objects or spaces that retreat from this envelope become warmer. For example, spaces and deep recesses within trees and rocks will often appear warmer than the less recessed spaces right next to them.
It's not an easy principle to grasp. Think of it as the sky being a kind of bluish gas that wraps itself gently around every object. There are problems with this model from a strictly scientific perspective but it makes a useful metaphor. As we understand with greater clarity the natural phenomenon of light and shadow we will paint paintings with even greater vibrancy and vision.
THE COLOR IT IS
One reason that color recipes for various objects or phenomenon, such as trees and shadows, so often fail is that the color of all objects changes depending on light conditions. Sometimes the color change is quite dramatic. For example, during the late moments of a sunset objects tend to appear as variations of orange in the light and variations of purple in the shadows. The local color, or the object color without any atmospheric perspective, will be nearly obliterated.
The best rule is that the color an object looks like is the color it is. That may seem obvious but I find I'm constantly attempting to paint local color, the color I remember an object to be, rather than the true color that is before my eyes. I have to subdue the impulse to paint my preconceptions and make myself aware of the true color by making myself conscious of other color possibilities. Knowing some color theory can be helpful to jar you into seeing reality as it really is.
The color of light at noon on a clear day is the whitest the light will ever be. The light can actually look cool and the shadows warm although I suspect this temperature inversion might be a field effect (but remember; the color it looks like is the color it is). Shadows at noon are the most neutral they will ever be. Morning light tends to be a cool pinkish color that changes to a cool yellow approaching noon. After noon the light begins to turn a warm yellow which gradually fades to orange then a warm red and finally to purple. Some see this as a type of iridescence or prismatic color shift. Of course, in a rainbow we do not see colors shifting toward white in the middle of the spectrum (although in the Kelvin Temperature spectrum we do observe this phenomenon). But a chromatic shift is an interesting metaphor and serves as an appropriate reminder of the shifting color of light.
Another interesting phenomenon of light is that it is the whitest it will ever be at its first reflection. For example, imagine light hitting rocks at noon when the light is whitest. This beam of light then reflects off another rock and as it does drops down a wavelength to a warm yellow. This light then bounces off another rock and drops another wavelength to orange and so on until in the deep recesses of the rock the reflected light might be a deep purple.
Some color theorists see complementary colors in shadows. For example, if the light is a lemon yellow the shadow would have a warm purple cast. In the western United States when we have one of our periodic forest fires the light becomes extremely orange as it is filtered through veils of smoke. At such times the shadows become an extremely bright cerulean blue. This could be the result of the smoke diffracting the blue sky and backwashing the bright blue into the shadows. But because the blue is so intense I suspect this phenomenon is partly an optical effect of the complementary color being projected into the shadow (otherwise known as field effects. See chapter x). Ultimately I agree with John F. Carlson who suggests that if you see complementary color in shadow by all means paint it in.
Given that shadow complementarity might be an interesting effect to include in your paintings from purely aesthetic reasons I prefer to keep my shadows complex by using at least two colors. For example, if I'm painting objects in a very orange light a reasonable field effect might suggest a blue shadow. But I find it more interesting if this blue is split into warm and cool versions. Because of the tendency of opposing colors to neutralize themselves the split can be quite diverse and still maintain a similitude of reality. For example I could paint the shadow with broken color comprised of a Thalo Blue warmed with a dash of Cadmium Yellow and a cool Dioxazine Purple. This would give the illusion of a bluish shadow but with a complimentary field effect.
Another aspect of painting the effect of light is that a surface will look more illuminated if it is painted with a lot of texture. Conversely, a shadow will look deeper and more convincing if it is painted thinly. Since everything is relative if you use a lot of thick paint in the lights you can use some texture in the shadows (it can look a bit odd if your lights are very textured and your shadows and reflections have no texture at all). To get a lot of textures in my lights I frequently use Gamblin's Lead White Replacement which, like its namesake, is very thick and will preserve the texture of your brushstrokes quite nicely (with the added benefit that it contains no lead). Another color I like is Gamblin's Radiant Lemon which is a hue of an eight value but is very useful (hues are pre-mixtures of basic colors, in this case Cadmium Lemon with Titanium White. The pre-mixture is a convenience to save time). Another great color to paint light is Gamblin's Transparent Orange, another hue, but it is a nice replacement for Indian Yellow (which I find has a slightly neutralizing gray undertone). To help keep shadows thin I will occasionally add M. Graham's walnut oil or Gamblin's Neo Megilp (which dries faster) to minimize and flatten strokes.
THE COLOR OF TREES
There are few things I enjoy painting more than trees. There is something just as mysterious and inviting about a cluster of trees as there is about a lone tree. It might be subtle value shifts, one of the hallmarks of true beauty, that intrigue me. But the same reasons that invite me to paint trees, their mystery, subtlety, and majesty, also makes them extremely difficult to paint.
The first and most important aspect of a tree, easy to overlook in bright glare, is that the main mass of a tree is basically one value. This is difficult to absorb because when you're looking at a tree it appears as though every value is represented in its form. But take the nine value grayscale outside and carefully note the values. You will be surprised at the closeness of the value range. The light and dark are often subtle variations of one basic value. Many people make the mistake of painting the foliage too light on one side. Or worse painting dabs of light all over the illuminated foliage. This gives a spotty, fractured look to what should read as one large shape (or value zone).
The second most important aspect of a tree is not the local color of the species, nor the texture of the leaves and bark, but rather the color of the light and the quality of the air that surrounds the tree. All trees project themselves into the bluish envelope of the atmosphere. So as a tree protrudes into the sky it will pick up more blue and its edges will turn bluer yet. At the base of the tree the reflected light from the ground will be warm. This warmth will be accentuated at the center of the tree where the light will get warmer and darker as it is reflected off of the bark and undersides of the leaves or needles.
Every tree should be treated as an individual. Masses of trees, whose values are so similar they read from a distance as one large value zone, can be treated as a group. But it is a grave mistake to paint any tree using a formula. That will lead to a mannered way of painting lacking the originality and surprise so necessary to great painting.
To paint trees well it is necessary to observe what you may now be failing to observe, the flurry of subtle values and hues that convey the beauty of trees.
THE PROBLEM OF RED
The reason I posed this question was that although I have a favorite blue (thalo blue), a favorite yellow (transparent earth yellow), as well as many others, I have yet to find a red that really thrills me like other colors of the spectrum.
So my lack of passion for red remains somewhat of a mystery. Some painters refer to red as the great moderator, meaning it needs to be felt in nearly every color as a unifying presence. For the time being, I suppose I will settle for reds that are useful. Among these I count quinacridone red, transparent earth red, and cadmium red light.
Some of my favorite painters use a limited palette. Followin fin their footsteps I tried using a palette of ultramarine blue, alizarin crimson permanent, and cadmium yellow light (I experimented with this palette for about six months). But with such a palette I found my paintings lacked complexity otherwise attainable by using additional hues. For me I found using a limited palette to be restrictive, and worse, it wasn't any fun.
On my monthly visits to the local art store I love to linger over the paint display finally settling on a strange color. I find adding an exotic color or two boosts my creativity. I have discovered quite a few colors this way that ended up in my pantheon of must-have colors. Occasionally I pick colors in relation to other colors. For example I love andanthrone blue because it's the perfect companion color to thalo blue. I also love dioxazine purple because it compliments transparent earth yellow so well. Transparent earth yellow is also a fantastic color because it is so dark out of the tube which gives a broader range of value.
I prefer some colors because of their tinting strength and purity of tone. Transparent earth red fits into that category as I find it stronger and cleaner than burnt sienna. Some colors are great because they make such wonderful grays. One such color is cadmium red light which mixes well with blues to make amazing grays.
Other colors are luxuries like transparent orange which although it is a hue (meaning it is a mixture of more basic colors) it is a beautiful one and difficult to mix. It is a great substitute for Indian yellow which I find has a slight gray undertone. I have no problem using hues if it saves time and generates the kind of creative enthusiasm I need to feel in the studio. Another hue I love is sap green as well as titanium buff and radiant yellow, two colors with lots of titanium white.
Although I feel I have settled into a selection of colors I feel comfortable with and can easily predict color mixtures, I see no need to restrict my palette if in doing so I limit my potential. In the final analysis I just love color too much to do without such beautiful possibilities.
THE PROBLEM WITH BLACK
Many painters avoid the use of black and prohibit it from their palettes. Theoretically there is nothing wrong with black. After all, the color paint looks like is the color it is, regardless of the name on the label. So if I add black to yellow to get green there is absolutely no problem provided the final color is the color combination I want (by combination mean that in loosely mixed paint there should be slivers of the original unmixed paint).
In a recent painting I avoided using blacks in the deep shadows. Instead I opted to mix two extremely dark yet highly saturated colors, Alizarin Crimson Permanent and Thalo Green, to create my darks. Using two deep colors to create a black allowed me to bias the color mixture to get rich, vibrating hues of either warm or cool variations.
If you are painting in the field and you need a deep, dark color to quickly add to other pigments you might consider using Gamblin's Chromatic Black which is a premixed combination of Thalo Green and Quinacridone Red. This mixture can be quickly made cool by adding Viridian Green or warm by adding Alizarin Crimson Permanent (or any warm color). Another favorite for making black is Dioxazine Purple and Transparent Earth Yellow (an extremely low value yellow). This mixture, when applied half mixed, creates a dark and rich color.
Black, like all other colors, will appear more vibrant if presented as broken color, or at least have elements of the basic components of other colors. For example a green will be more vibrant if it has flecks of blue and yellow sparkling through it. Just because an area in your painting is dark doesn't mean it shouldn't vibrate with broken color. And using half mixed, complementary colors will make this vibration easy and satisfying to accomplish.
GET YOUR GREENS RIGHT
There is no substitute for accuracy when painting greens. The sensitivity of the human eye to greens is more acute than with any other color. If your greens are haphazard or arbitrary viewers can easily detect your slothfulness. So how do you get the greens right? Use lots of red to mellow or soften the high saturation of green. To start a green I usually begin with Thalo Green to which I might add Alizarin Crimson or Cadmium Red. To modify this base I will add Dioxazine Purple to create a shadowy green. To mix a light green I add Cadmium Yellow Deep (an orange yellow). I use purple and orange to modify my greens because these colors contain a lot of red. If I add Cadmium Yellow Light and Ultramarine Blue (two colors containing little red) I push the green back to a highly saturated green and lose the advantage originally created by graying a base green with complementary red. I learned this by painting in Door County, which is much greener that my home in the deserts of Utah.
In order to capture rich greens I had to radically modify my methods of mixing but found the new procedure to be superior in achieving rich, subtle greens. Paradoxically the more green nuances you can mix the more greens you will see.