Tuesday, November 11, 2008

Color Theory

To master colors in your photographs, it helps to fully understand how technology represents those colors

This Article Features Photo Zoom

4) Installing ColorSync Profiles
For the purposes of this article, I’ll default to the terms hue, saturation and luminosity because they’re useful terms for working in Photoshop where they describe blend modes and are nearly identical to the HSB readouts in Photoshop’s Info palette. These three elements can be represented numerically. Photoshop provides readouts in its Info palette in several color modes, including HSB (hue, saturation, brightness), found in the submenu beneath the arrow. Luminosity is represented on a scale of one to 100. It’s a scale of 1 to 10 times 10. Put another way, it’s the photographic Zone system times 10.

This representation of color makes a numerical language for hue conceptually challenging. Several things will make using this scale easier. You can think of the color wheel as a clock, where every hour (or 360 degrees) you get a new color. The wheel starts at a warm yellow-red (0 degrees), 30 degrees is orange, 60 is yellow, 90 is warm yellow-green, 120 is green, 150 is cool blue-green, 180 is cool green-blue or cyan, 210 is blue, 240 is warm red-blue, 270 is purple, 300 is magenta and 330 is cool blue-red.

5) Chromaticity Diagram
An image could be considered to be monochromatic if it uses hues constrained within 30 degrees or less from one another. Analogous hues are within 60 degrees of one another. Complementary hues are 180 degrees apart. Linguistic descriptions of color are less precise than numeric descriptions of color. Consider forming consensus around terms such as “sea foam” or “dusty rose.” What color is mauve? More to the point, how many colors can the term “mauve” describe? Using numbers to describe the elements of color leads to a more precise definition of color. Consider the usefulness of specification systems like Pantone. In numerical systems there’s only one color for a single number or set of numbers. In addition to precision, one of the characteristics that makes a numerical system useful conceptually is its simplicity. Compare memorizing the numbers in the Pantone system with understanding the numerical scales in HSB. Not all systems are simple enough to be used conceptually; HSB is.

6) Complementary Axes 7) Complements Warm
8) Saturation Level
9) Structuring Hu

Words and numbers provide one kind of perspective, pictures represent another. Color can be graphed. While color has three components, it’s typically graphed in two dimensions. (The widespread use of computer imaging and its potential for 3D imaging may change this in the near future, but it hasn’t changed yet.) This means in any two-dimensional diagram of color, the representation of one element of color is limited. Nonetheless, even two dimensionally, graphing color is quite useful. A classic way of representing color is in a circle or wheel. Creating and using color wheels to describe color and analyze color relationships is a time-honored tradition dating back to Leonardo da Vinci.

Newton, Goethe and Munsell created some of the most famous color wheels. Color wheels can be particularly useful when colors are plotted on them and when geometric shapes are imposed upon them. You’re then able to identify a variety of relationships between colors, both colors that exist in a composition and colors that do not.

A straight line can be drawn through the center of the circle to define warm versus cool colors (a specific line between 90 and 270 degrees) or to identify complementary colors (any line). Concentric circles can be used to define the level of saturation a color or set of colors contains. Triangles can be used to identify types of color interactions—primary or secondary colors, monochrome, analogous or complementary colors. More complex geometric shapes—triangles, rectangles, pentagons, hexagons, octagons—can be used to help identify colors that may be used with one another to create logical color structures. For this, you’re likely to find the Apple color picker (a wheel inside Photoshop) particularly useful (Photoshop > Preferences > General > Color Picker > Apple). Color wheels are excellent for displaying relationships between hue and saturation, but are limited in their ability to display corresponding luminosity relationships.

There are many other useful terms in the lexicon of color theory and distinctions that can be made, but the elements mentioned here are the essentials on which you can base your conceptual foundation of color. With this language of color at your disposal, you can sharpen your perception of color, better understand existing color dynamics, make predictions about how color modifications will affect an image and communicate more clearly about color—before, during and after working with color.

John Paul Caponigro is an internationally respected fine artist, author of Adobe Photoshop Master Class and the DVD series R/Evolution, and a member of the Photoshop Hall of Fame. Read more of his R/Evolution columns online at www.digitalphotopro.com. Get over 100 free downloads and his free enewsletter Insights at www.johnpaulcaponigro.com.


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