IntroductionColor VisionMixing LightSubtractive ColorPaintingPhotosPrinting


Photography has gone digital. However, much can be learned about color mixing by understanding how the older color photography used color film, transparencies, negatives and photographic paper to produce color images. Most of these film products were coated with color dye layers that act as filters to stop various amounts of color light from passing through. Since these color layers can hold back light passing through them, the photographic process makes use of the "subtractive" system of color mixing. It subtracts the colors out of the light that is reflected or transmitted.


How do the color layers in a film photo form a full range of colors?


The three color layers are three photos of the same scene. The amount of color in each layer matches the amount of each color of the 3 primary colors in the original scene. The cyan, magenta and yellow layers subtract color from the light that you use to view the photo. Since the layers are transparent, all three layers can be seen at the same time.

Look at the image above. Notice that the white portion represented by the frost on top of the apple has no color in any of the layers. What you see as white is really the paper backing of the photograph showing through, since no light is being subtracted in that part of the picture.

You can see that the green in the image of the leaf is formed by the combined colors cyan and yellow in those two layers. The red of the apple comes from the layers for magenta and yellow. If all three layers had the maximum amount of color in each, then that area would look black. All light would be subtracted (absorbed) in that case.

From subtle to intense colors can be found in color photos All other colors are made by variations in the amounts of color in each of the three layers. For example, each layer can range from a very deep color to a very pale shade. Some photos may have many different colors and shades of color. Some colors may be bold and others hardly noticeable, but there are still three basic color layers.


                             BLUE                    YELLOW


When the colors of a picture are reversed, the negative image that results produces opposite or complementary colors. The colors in a color film negative are the opposite of the colors in the final photo paper print. Notice that the flower that appears as red in the negative image is actually a cyan flower in the positive photo. The flower that appears green in the negative turns out to be a magenta flower. The flower that appears blue in the negative is yellow in the photo. So once again we can see a relationship between the red, green and blue of the "additive" primaries and the cyan, yellow and magenta of the "subtractive" color primaries.

(The typical photographic negative film contains two additional color layers besides the color negative image. These two extra layers form a "mask" to correct for limitations in the color filtering properties of the negative dyes when printed on photographic paper. It is this built-in mask that gave film negatives their characteristic color which may appear an overall orange to brown color.)


Digital photography does not require film. It is a photo-electronic process. Digital photos also utilize a number of basic colors to produce a range of millions of colors. Digital cameras mostly rely on light sensitive chips with filters that separate an image into its basic colors for processing electronically. For the most part, cameras utilize the red, green and blue colors of the "additive" primary colors.

Digital photography can be displayed electronically on screens and monitors. These screens and monitors most often use the "additive" primary colors of red, green and blue.

Digital photos can also be printed out on paper using a color printer. The "subtractive" color system is used, which usually includes at least cyan, yellow and magenta inks.


  Next: Printing  
All text, images and animations are by Robert Truscio © 1997, 2016.