Color Theory
A primary color is a color that cannot be made from a combination of any other colors. A secondary color is a color created from a combination of two primary colors. Tertiary color is a combination of three colors (primary or secondary).
Printers and artists have different definitions for primary colors. The traditionional primary colors that painters have used are red, yellow, and blue. Modern printing press secondary colors are magenta, yellow, and cyan. These two primary color systems obviously do not agree. Additive and subtractive are the two primary methods for reproducing a range of color.
Additive Color
Additive color synthesis is the creation of color by mixing colors of light. Human
vision relies on light sensitive cells in the retina of the eye. There are two
basic kinds of sensors. These are rods and cones. Rods are cells which can work
at very low intensity, but cannot resolve sharp images or color. Cones are
cells that can resolve sharp images and color, but require much higher light
levels to work. The combined information from these sensors is sent to the
brain and enables us to see.
There are three types of cone. Red cones are sensitive to
red light, green cones are sensitive to green light, and blue cones are
sensitive to blue light. The perception of color depends on an imbalance
between the stimulation level of the different cell types.
Additive color processes, such as television, work by having the capability to generate an image composed of red, green, and blue light. Since the intensity information for each of the three colors is preserved, the image color is preserved as well. The spectral distribution of the image will probably be wrong, but if the degree of intensity for each of the primary colors is correct, the image will appear to be the right color.
The three primaries in light are red, blue, and green, because they correspond to the red, green, and blue cones in the eye. Example 1 shows how the light from red, green and blue flashlights would appear if shone on a dark wall.
Red + Green = Yellow
Red + Blue = Magenta
Green + Blue = Cyan
Printers' primaries—yellow, cyan, and magenta—are typically used by professional designers and printing presses .
When all of the colors of the spectrum are combined, they add up to white light.
2 parts Red + 1 part Green = Orange
2 parts Green + 1 part Red = Lime
4 parts Red + 1 part Blue + 1 part Green = Brown
Subtractive Color
Subtractive color synthesis is the creation of color by mixing colors of pigment, such as paint or ink in your computer’s printer. This type of color is what is used in the art and design world. When learning basic color theory, art students typically use familiar colors like red, yellow, and blue.
Subtractive color processes work by blocking out parts of the spectrum. The idea of subtractive color is to reduce the amount of undesired color reaching the eye. If, for example, you had a yellow image, you would want to have a dye that would let red and green reach the eye, and block out blue. The additive secondaries become the printers’ subtractive primaries, because each of the additive secondaries will reflect two of the additive primaries, and absorb one of the additive primaries.
The three primaries on the artists’ color wheel are red, blue, and yellow. Example 2 illustrates subtractive color by showing how primary colors mix on a piece of white paper.
Yellow + Blue = Green
Yellow + Red =
Blue + Red = Violet
When all of the colors are combined, they create black pigment.
Additive Primaries/Secondaries Absorption Chart
|
Color |
Reflects |
Absorbs |
|
Yellow |
Red and Green |
Blue |
|
Magenta |
Red and Blue |
Green |
|
Cyan |
Green and Blue |
Red |
With this information, if we wanted red, we would mix
magenta and yellow. Magenta would absorb green, and yellow would absorb blue,
leaving only red to be reflected back to the eye. For black, a combination of
all three would be used, which should block out all light in theory. Printers
use black as well, since the dyes used in printing are not perfect, and some
light from other parts of the spectrum gets through.
For printers’ mixing:
Yellow + Cyan = Green
Yellow + Magenta = Red
Cyan + Magenta = Blue
Description of
Lightness (brightness) – Is the lightness or darkness of the color, the amoung of light reflected or transmitted.
Saturation – Is the level of white, black or grey, ranges from neutral to brilliant (pastel to full color).
Tint – Base color plus white.
Tone – Base color plus grey.
Shade – Base color plus black.
Value – How light or dark a color is.
Aggressive - AKA 'Warm'. The yellows, oranges, and reds. These come towards the eye more (spatially) and are generally 'louder' than passive colors.
Passive - AKA 'Cool'. The greens, blues, and violets. These recede from the eye more (spatially) and are generally 'quieter' than the aggressive colors.
Achromatic – An achromatic color scheme is one that is
colorless – using blacks, whites and grays.
Complementary – A
complementary color scheme is one that uses colors directly across from each
other on the color wheel. This can be accomplished by using two colors or hues
that are opposites such as red and green or violet and yellow. In this color
scheme any two complements, all the semi-neutrals and the neutral they produce
can be used. Black and white can also be used. Since you can choose from
varying colors and hues which can give a bold and dramatic effect, this color
scheme is best used for dramatic,
strong, or bold statements.
An example of a complimentary color scheme
Monochromatic – A monochromatic color scheme is a one-color color scheme. However, the color can be neutralized by adding its complement to lower the intensity of the color. Black and white can also be used to darken and lighten the value of the color. It is achieved by using one color or hue, utilizing that colors’ various tints, tones and shades. Using a monochromatic scheme with multiple textures creates character and maintains unity.
An example of a monochromatic color scheme
Analogous – An analogous color scheme is any three adjacent primary, secondary, or tertiary colors on the color wheel. These schemes can be warm or cool. Each can be neutralized by use of its complement, and black and white can be used. Analogous colors "harmonize" well and produce a definite mood to a composition. This can create a very harmonious color scheme.
An example of an analogous color scheme
An example of a color triad