Today we dive into color theory and I apologize in advance if it gets complicated, but I will try to keep it in layman’s language. The science of color is a field unto itself, but we are only going to touch the big ideas. We almost never want to use a tube color on the canvas since it is always garish.
The Color Wheel
The standard color wheel shows the easiest visual description of color theory. It shows yellow at the top and blue 120 degrees away (bottom left) and red on the lower right. The obvious secondaries are violet between blue and red, green between blue and yellow and orange between yellow and red.
This is where most artists stop in their color theory, but there is so much more you can see from this one simple chart. Obviously the warm colors are to the right of yellow to purple. The cool colors are on the left. Simple so far.
Almost every color needs to be “ripened” or “aged” by adding the complementary (opposite color on the color wheel) so the color isn’t garish or look like poster colors.
The Color Sphere
When we begin to adjust our pure tube colors, we move to a different place in a sphere. This matters because we need to know what the opposite of that color is in order to neutralize a pure color with it’s complementary (the color opposite it on the wheel-a secondary color).
Color purists never ever use black form the tube, they prefer to mix their own from opposite colors, like medium cadmium red and phthalo green. The red is opaque while artificial phthaloes are dyes and thus much less opaque.
To be sure you have a close enough grey, mix in a bit of white. You’ll know instantly if it is a neutral grey or biased toward red or green. You want to know this because to properly neutralize a color, you have to mix the exact opposite. Or as close as you can manage. Early in your learning process, this won’t matter much, but as you progress you will see colors more accurately and thus will want to be more exact.
Color Theory in Practice
Another situation is when you want to warm up a color or say you want to cool the color in the shadow of an object. So for fun, let’s say we have a bright red ball, so the shadow side will be almost a rust red and deepen toward a grey-black at the bottom of the shadow.
So looking at the color wheel or the sphere, we want to neutralize the bright red. Find the closest red on the wheel, (most likely a warm red since it is well lit) and find the closest green opposite that red color. You may have to adjust your tube green with blue or yellow to get closer. Once you have found the best opposite, add some to the red in a separate spot on your palette. If it is a true complementary, you will get a nice chromatic black.
Some Practical Science of Color
In very simple terms, every color corresponds to a specific wavelength. Violet has very short wavelengths and reds have much longer. This matters when you look at a color graph to see what colors are included in a sample. And it can be very instructive for understanding color.
What we see here is that a luminous green is most visible to the human eye. Fortunately for our discussion, it also happens to show the mix of yellow and blue in the specific green. If this were a pure color, the graph would show a sudden very narrow hill.
But what we see here is that the color is comprised of blue to the left and yellow to the right. Obvious but a very clear demonstration of the truth of the color theory above.
I hope I haven’t confused you, but knowing a bit about the theory behind color will help you mix colors more accurately and give you richer, aged colors, pleasing to the eye of the viewer.