Complexity of Color - Part 1

At first glance, it would appear that color is a pretty simple concept. You look at grass, and it's green. You look at a (red) rose, and it's red, right? The complex part comes when you want to take what you see and end up with a printed product accurately reflecting the image you see with your eyes. The color spectrum visible to the human eye is represented by this image:

Devices used to capture an image (film in a camera, the scan of that film, a digital camera image) have a more limited ability to "see" the colors. Once the image is digitized and viewed on a computer monitor, it is an rgb (red, green, blue) image. That is, all the colors you see on a monitor are made up by varying the luminosity of those three colors. For example, all three colors "switched" off gives you black. All three colors displayed at their maximum intensity make white. All the colors inbetween are produced by the blending of these three colors at varying brightness that takes place at the viewer's retina. Color produced this way is known as an additive mixture. The triangles in this image:

represent the color spectrum able to be reproduced by two different monitors compared to what the human eye can see. As you can see, not only is the reproducable color spectrum much smaller than the human eye can see, different monitors will vary in their display of the digital image depending on the monitor calibration.

Enough for the exiciting introduction... Next time I'll discuss proofing and printing methods and some challenges inherent in reproducing color images on paper.

© 2005, Bob Cooper