TECHNIQUE

COLOR THEORY

It is said over a hundred years ago the Impressionists used complementary colors – those opposite on the color wheel -- to under-paint their works. In college I took a course in visual perception and learned about “after-vision” or “ghost” colors. These are obtained by staring for 30 seconds at a color and then gazing at a white sheet of paper. A ghost-like color appears in one’s vision after a few seconds.

I remembered the Impressionists’ technique when I started painting seriously about 25 years ago. I also recalled my college class and wondered about the effect of under-painting with ghost images, instead of complementary colors. I tried it. The results were stunning. By not completely covering up the under-painting somehow the eye blends the opposing colors and objects are set in space in a unique and fascinating way.

In a color wheel, complementary colors are supposed to be directly across from each other. My experiments show that for the most part the opposite colors are not ghost images of each other. This has caused me to question the whole opponent process theory of color vision. Wikipedia describes it like this: “The opponent color theory suggests that there are three opponent channels the cone photoreceptors are linked together to form three opposing color pairs: red versus green, blue versus yellow, and black versus white (the last type is achromatic and detects light-dark variation, or luminance).” I think the theory is basically wrong.

People have three types of cone cells, corresponding to sensitivities to short (indigo/violet), medium (greenish) and long (orange/red) wavelengths. Pictured above is a graph that describes them from Wikipedia.

You can see how there is overlap and so one supposes that the receptors work in concert with each other where there is overlap. It seems to me that a “ghost image” comes from the fact that staring at one color momentarily weakens the photo receptor primarily responsible for a given color, allowing the other receptors to assert themselves.

I created a new “ghost color” wheel to expedite my painting process.

The inner portion is the traditional wheel. Pick a color. Its “ghost” twin adjoins it in the outside ring. You will notice that there is no pure red ghost image. The closest one comes is the sandy/orangey color associated with the light blue. Is this because when you knock out the blue, you allow both the red and the green to assert themselves (red and green make orange…)? Similarly, when you knock out the long wave (orange/red) cone, are you allowing the green and indigo to mix to blue? I do not know for sure, but what I do know is my new color wheel works magnificently as an aid to painting.

PAINTING PROCESS

It is too challenging to paint on a pure white canvas and so it must be toned by rubbing thin Payne’s Grey or dilute Umber acrylic paint on it to kill the glare. Next, vine charcoal is used to quickly sketch the image. It is then lightly rubbed off, leaving a faint residue of the drawing. A “liner” brush is then used to go over the charcoal drawing with umber or burnt umber, creating a permanent outline.

Once the line drawing dries, one can start “coloring” the canvas. (Yes, the very skill you learned in first grade!) Next I under-paint the large, main masses in every painting with acrylic “ghost” colors. This need only be roughly done, since all will be over-painted. Acrylic is used because it dries right away and one can immediately start the top colors in oil.

By painting on top of what is essentially a color negative, one sees clearly hues and values (lightness or darkness) and it is much easier to mix the proper color to match the image you are painting.

My style is “painterly” meaning I mostly do not smooth away the strokes. By leaving at lease some of the underpainting peak through you allow the eye to blend the colors.This gives your images in space in a way like no other.