Light & Color

Light and Color

The main difference in how photographers and painters work with color is that photographers work with light and the film or digital sensors necessary to capture that color from light, and painters work with pigments and the medium necessary to build those colors. Both color mediums only exist under the conditions imposed by artificial or natural light.

That light is the source of color was first demonstrated in 1666 by the then 23 year-old Isaac Newton, who passed a beam of light through a prism, producing a rainbow of hues of the visible spectrum. This had been observed before, but it had always been related to the latent color in the material of the glass. Newton took this experiment a step further and passed his miniature rainbow through a second prism that reconstituted the original white beam of light.

His conclusion was revolutionary: color is in the light, not in the glass.

The color from light is an additive process. The color from pigment is a subtractive process.

Black and white are two completely different phenomena in terms of light and pigment. White light as Newton demonstrated is the addition of all the separate wavelengths of color. In pigment, it is the reflected property of the light wavelength for visible color. The apple appears red because the red wavelength is reflected and all the other wave lengths of the colors of the white light spectrum are absorbed.

In pigment, black is the mixture of all the color properties or wavelengths of light so that all the light is absorbed and no wavelength of color is reflected back.

Basically then, to make colors, depending if you are a photographer or a painter, is by adding or subtracting. Photographers however can subtract color wavelengths by using color filters over their lenses. For example a yellow filter blocks blue and a magenta filter blocks green and a cyan filter blocks red.

Early color photography used an additive approach to color, but it is much more practical in terms of film processing in the lab to use a subtractive method to attain color.

This principle is based on the fact that the primary colors of red, blue and yellow produce about one third of the light spectrum each. As light when they are all added together they produce white. So blocking one lets in two-thirds of the other. Blocking all equals black.

In film, there are two methods for reproducing color: color negatives and color transparencies or color slides (positives).

In color negatives, a reversal process is recorded as three superimposed black and white images in three layers of emulsion, each sensitive to red, green or blue. In color slides (positive images), the emulsion is exposed a second time to produce dyes forming the three colors.

But it is a very complicated chemical process.

With painters, the process of creating color involves mixing pigments and then tinting or shading depending on how light or dark the painter wants the color. A scale, similar to the gray scale in black and white photography (which is calibrated from the first shade of visible difference from matte white to the last shade of dark before matte black). This is called the “relative value” of a color. When we speak of dark blue or light blue we speak about a color’s value, its lightness or darkness. Whenever white is added to a color (its basic “hue”) we are speaking of a “tint” of that color. Whenever black is added we are speaking of a “shade” of that color.

The spectrum of color is divided into a series of thirds or “primary colors.” Each third can be divided again into thirds to produce “secondary colors” and into thirds again to produce “intermediate colors.”

This is the standard wheel of color of light separated by a prism.

The primary colors of RED, YELLOW and BLUE are so called because mixing cannot make them. Mixing two primary colors can make the secondary colors of ORANGE, GREEN and VIOLET.

Red + Yellow = Orange

Yellow + Blue = Green

Blue + Red = Violet

And intermediate colors are mixtures of a primary and a neighboring secondary.

Red-orange

Red-violet

Yellow-orange

Yellow-green

Blue-green

Blue-violet

After color (hue) has been established, it is given an intensity and value. Intensity is how bright or dull the color appears. A color is dulled down by either adding gray or the hue opposite it on the color wheel. In the case of Red, adding Green (which is opposite) lowers (dulls) the intensity.

Analogous colors are colors that neighbor each other on the color wheel. We think of color in terms of relative warmth or coolness. Combinations of red, yellow and orange give warmth, and blue, green, violet cool down. When these color temperatures combine and contrast a color tension is created.

Try this experiment at home. Get some red and white construction paper and place them side by side a couple feet in front of you under a bright white light and stare at the red paper for one minute without blinking. Then shift your eyes to the white paper. What color do you see?

You should see red’s opposite—green. This effect is called “simultaneous contrast” and is due to the way our eyes work in creating “afterimages” of a given hue in the color of its complement. Because of this relationship of complementary color, Albert Munsell in 1905 created a color wheel based on five rather than three primary hues: yellow, green, blue, violet and red. This reflected more accurately, the way human eyes gauged color complements.

Painters concentrate on four basic areas when choosing color as the subject or part of the composition: local color, optical color or “perceptual color,” and arbitrary color. And of course, these color schemes can be used symbolically to express a feeling or mood or an idea.

Local color is what the object is normally associated as being: green grass, blue sky, red sunset, etc.

Optical color is how the eye perceives color as colors change atmospherically. A distant hill covered in forest at sunset appears bluish not greenish. Impressionist painters who painted outdoors were aware of these subtle changes in the way light affected color. So they painted optically.

Arbitrary color is using any color to represent objects. If a painter wants to paint a green sky that is using color arbitrarily.

Symbolic color is when a color is used to express a painter’s psychic or emotional state. Van Gogh’s “The Night Café” is an example of how garish red and green clash to create tension and in a letter to his brother Theo, Van Gogh explained that he was symbolically using red and its opposite green to symbolize a place where evil can happen and madness result. It is interesting to compare Gaugin’s painting of the same café.

As an exercise, search for a painting or photograph that uses color symbolically and explain what you believe the color represents. Or look for a painting where color tension is created by the use of warm and contrasting cool colors.