Sunday, January 6, 2013

Color, Part 1: The Basics


Constanec-Prepress-web
So, I want to talk with you today about color. If I have time I’ll get into the knitty-gritty of our process here but first I am going to start with the basics.
Color is light. You may remember a high school science class where you learned that the color that an object appears to be is that way because the objects surface is reflecting only that color of light. Let’s take an apple, a juicy red apple, as an example. The light that strikes the surface of the apple contains every color in it. The cells that make up the skin of the apple contain pigments that absorb every color of the light spectrum except red. So, the light that reflects off the apple is only red giving the apple it’s red appearance. Different colored apples simply have different pigments in their skins which absorb different sets of colors.
Did you notice the word pigment in that paragraph above? What that paragraph just described is called subtractive color. All pigments work on this principle; oil based paint, watercolor paint, Copic markers, printer toner, and the dyes used on cloth. They all create the color we see by absorbing, or subtracting, all of the other colors that occur in light. But, what about a computer monitor? You know the thing you are looking at right now?
A computer monitor, actually every monitor, works by shooting white light through a grid of red, blue, and green pixels. I’m going to give you the logical explanation for how displays work, not the physical. Each pixel in an LCD actually contains all three colors but we’re talking about color not LCD design. So, if the only colors a monitor can make are green, blue, and red, how do you get yellow? Or any other color that isn’t green, blue, or red, for that matter? Easy, the display makes yellow by shooting a bean of white light through the green and blue pixel at the same time. And, the brightness, or strength if you want to think of it that way, of the white light determines whether we see a dark green or a neon green. This is called additive color.
Now, here’s where things get interesting (read very difficult). Angela makes a beautiful watercolor painting of her autobio character eating her own entrails and she wants me to digitize it so every one on the web can see it. She also wants me to prepare it for print so we can sell a big poster of it.
The original art work uses pigments so the colors are subtractive and the pigments are analog so they have perfect smooth and continuous transitions from color to color and shade to shade. The digitizing process captures the reflected light from the art work and it does it digitally which introduces a bunch of complications that I will be getting into in my next article.
How’s that for a tease!
Constance

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