Color Theory 101 – Color and light, RGB, CMYK, Color wheel, Harmonies and much more

This Color Theory 101 is a practical guide for designers to help them understand better this complex and so important subject. This article is not too technical, we’re going to study colors in an applicable way, talking about how do they work, color characteristics, additive and subtractive color, color harmonies and resources.

COLOR AND LIGHT
We can say that color is basically a matter of light. Without light there’s no color. So, how does it work and how can we see colors? First, white light contains all the visible spectrum colors. It means that these colors together, with the same intensities, make the white. The light from the sun, for example, is a white light. We can see that it’s made from all the colors in the rainbow, when the sunlight is decomposed.
Take a look below at how the light and colors work:

- The white light from the sun reaches the object.
- All the colors are absorbed, except the red.
- The red is the color that we see.

HUE, SATURATION AND BRIGHTNESS
There are three main characteristics that can define color: Hue, Saturation and Brightness. The hue is the color itself, as you can see the variations in the image below. The saturation refers to the amount of color that distances it from the gray (a grayscale image, for example, is fully unsaturated). The brightness refers to the amount of black or white in the color. This is how the HSB system works, based on these values to create any color.

ADDITIVE AND SUBTRACTIVE COLOR
We can work with these two color models, each one, for its own purposes. The additive model is based on mixing the light, while the subtractive model is based on mixing the pigments. In a simple way, we work with the additive model (RGB) when preparing contents to be displayed on tv, internet, mobile or any light source. When working for printing, we work with the subtractive model (CMYK).

Notice something interesting: the mixing of RGB creates CMY colors, while the mixing of CMY creates RGB colors. And again, the mixing of light colors creates white and the mixing of pigment colors create black.

COLOR WHEEL
The color wheel is the circular organization of colors according to hue. This representation is based on the primary colors (according to the standard color wheel: RYB) and shows the mixing between them.
The image shows a simple color wheel that will guide us when talking about color harmonies. Attention to the primary, secondary and tertiary colors in different sizes.

COLOR HARMONIES
Let’s see some of the combinations that we call harmonies. They tend to compose a good combination, but, of course, any project has its particularities.

Complementary Colors
The complementary color makes a high contrast layout, use carefully.

Double Complementary

Double Complementary

Analogous
The analogous harmony has a low contrast and makes a softer pallete.

Analogous with complementary

Tetrad

Triad

WARM AND COOL COLORS
We can separate colors in warm and cool. The warm colors are the ones close to orange, red and yellow. The cool ones are next to blue, violet and green. The image shows the “line” between them. Adding warm colors make the layout more cozy, happy and vibrant, while using cool colors make it more cold, serious and formal.

RESOURCES AND TOOLS

Colour Lovers

Community for color inspiration

Kuler

Adobe’s tool for creating and sharing color palettes

Color Blender

Create color palettes online

Color Jack (Studio , Galaxy and Sphere)

Three different tools for creating color schemes

Colourmod

DHTML color picker

Color scheme designer

Color palette genarator according to various harmonies

Color Schemer
An application that works suggesting combinations for you

Daily Color Scheme

Every day with a new beautiful color scheme

Color Combos

Browse through lots of combinations from the library

Color Filter (Color Blindness)

See any website as a color blind person would see it

Easy RGB

Create color harmonies based on RGB values

ColorZilla

Firefox add-on for designers, with handy tools

LINKS

How to use colour in logo design
Color perception
What’s your favourite colour
Test your Color IQ