Color theory
From open-encyclopedia.com - the free encyclopedia.
In the arts of painting, and photography, color theory is a set of basic rules for mixing color to achieve a desired result. As pigment and light are different in terms of how they combine to create colors, so too are the rules for dealing with each. White light is composed of the three primary hues, while combining these same hues in pigment will produce a black color.
| Contents |
Color Models
In strict traditional artistic and painting concepts, red, yellow and blue are the primary colors, and all other pure colors can be created by mixing red, yellow and blue paint. Many people learn a bit about color in elementary school by mixing paint or crayons in these primary colors. However this red/yellow/blue color model is rarely used outside of paint-pigment mixing.
The color model used when mixing colors of light is Red/Green/Blue, commonly called the "RGB Model" or "RGB color space". All other pure colors can be created by mixing these three colors. All these colors mixed together create white; when no color present the color is black. Consequently this model is called the additive color model, as new colors are created by adding colors. The RGB model applies to computer monitors, television and video projectors, all of which use red, green and blue pixel elements to represent every color.
For printing purposes, the colors used are Cyan, Magenta and Yellow; this model is called the "CMY model". In the CMY model, black is created by mixing all colors, and white is the absence of any colors (assuming white paper). As colors are subtracted to produce white, this is also called the subtractive color model. A mix of Cyan, Magenta and Yellow actually gives a muddy black so normally black ink is used as well; when black is added, this color model is called the "CMYK model". CMYK colors cannot be mixed to produce white, so printing in full color on colored paper may require the addition of white ink.
A much more detailed discussion of color models, particularly as they apply to color for computer displays, can be found in the color space article.
The Color Wheel
Traditionally colors are represented on a wheel of 12 colors: three primary colors, three secondary colors (created by mixing primary colors) and six tertiary colors (created by mixing the primary and secondary colors). Artists use a traditional color wheel based on the Red/Yellow/Blue model with secondary colors of orange, green and purple. For all computer-based color, a wheel based on the RGB model is used; this encompasses the CMY model as well since cyan, magenta and yellow are the secondary colors for red, green and blue. (Conversely the secondary colors for cyan, magenta and yellow are red, green and blue.) In the RGB/CMY color wheel, orange is a tertiary color between red and yellow and purple is a tertiary color between magenta and blue
Tints and Shades
The color wheel is based on "pure" colors; for every color there are also darker and lighter versions. Darker versions are produced by adding black or removing light, and are called shades; they are sometimes also called "deep" or "dark" colors. Dark shades of yellow, oranges and some reds are typically called browns. Lighter versions are produced by adding white or more light, and are called tints; they are also sometimes called "pale" or "light" colors. Very light tints are also often referred to as "pastel" colors; light tints of some reds, oranges, and yellow are tans.
Color Harmony and Color Schemes
Harmonious colors are colors that work well together, that produce a color scheme that looks attractive; the color wheel can be used as a valuable tool for determining harmonious colors. Complimentary colors are colors directly across form each other on the wheel. These are typically colors that will produce a strong contrast. Split complimentary colors are those on either side of a complementary color; these colors contrast, but not as strongly as complementary colors. Triad colors represent three colors equidistant on the color wheel; this typically provides a balanced color scheme with reasonable contrast. Analogous colors are colors next to each other on the color wheel. They typically harmonize well but may not provide enough contrast, and are perhaps best used in conjunction with a complimentary color. Monochromatic colors are all shades and tints of the same color.
Cool and warm colors
Warm colors are red, oranges, yellows and green-yellows, and are typically thought to express warmth, comfort and energy. These colors also tend to make things stand out from the page or screen. Cool colors are violets, blues, aquas, and greens. Purples can be warm or cool. When they are used together, cool colors seems to move away from the viewer, and express coolness, detachment, stability and calmness.
Neutral Colors
Black, gray and whites are neutral; browns, beiges and tans are sometimes considered to be neutral as well. Neutral colors are intended to send no messages but often work harmoniously with other colors. They are sometimes thought of as colors "off the color wheel".
Schemes from Nature
Combinations of colors found in nature often work well as color schemes even if they don't fit specific patterns discussed above; examples of these schemes include "autumn colors" and "spring colors"
Color in Painting
In painting the well-known "color wheel" is a tool to teach beginners the essential relationships between color hues: The primary colors (red, blue, yellow) are combined to form the three secondary colors (purple, green, orange) in a hexagon. A primary color (R,B,Y) will have a secondary color for its opposite —ergo red's complement is green, blue's is orange, and yellow's is purple. Adding a complementary color to a color on the canvas is the traditional technique for making shadows, as well as for choosing a balance of color overall, that the eye does not tire from an overuse of red, for example.
Shadows
In color theory, "shadows" generally refers to a general choice between adding black pigment, or using a complementary color to contrast a color, thereby making it darker by mixture or by optical illusion. The reason is that adding black to make a shadow tends to flatten the painting —neutralizing any dynamic color interactions that would otherwise occur. Adding a complement, accomplishes the task of defining the darker area, and at the same time, adds another color, creating a more realistic and dimensional look.
Pigment
Depending on the quality of the paint, the balance between colors varies greatly with pigment. One way to test the quality of oil paints is to make a sample of black by mixing the primary hues. To produce black, blue and red are mixed to a dark purple, which is gradually bent toward a colorless black by adding smaller amounts of yellow. Testing the balance of the mixture simply requires separating a small portion and adding white spreading the grey out on the palette. If the grey is colorless, then the black is pure. Poor pigment quality makes a muddy, purplish/greenish glob, while better paints will blend to black or very close to it.
