CGM!
Composite GIF Machine

The 'plain' machine.

Still broken, working on it.

Your computer monitor is filled with tiny specks of light called pixels.

Each pixel is made of three color components: red, green, and blue.

If an area of pixels is filled with a single color we see only that one color:

redgreenblue

If an area is filled with pixels of two alternating colors the mind composites them together, and effectively sees a 'different' color. Here are three examples of composited colors, plus an enlargement of the two colors used to make the 'new' color:

red plus green =

red plus blue =

green plus blue =

As a further refinement, each pixel may have a different level of value, yielding slightly different colors:

Now here's the part you're not going to like, but I will make it as painless as possible. Each level of color is represented in hexadecimal numbers. The good thing is that for this purpose there are only six of them: 00, 33, 66, 99, CC, and FF. 00 is the lowest (dimmest) value, FF is the highest (brightest) value.

In the samples above all colors are set to their highest (brightest) level, FF. In the next examples certain colors are set much 'dimmer'. That is a lower light level, and the composite produces a different color.

red (FF) plus green (66) =

red (66) plus blue (FF) =

green (FF) plus blue (66) =

Clear as mud? :) It's not necessarily 'easy', but it's not rocket science either, and what's happening will become clearer as you play with...

The 'plain' machine.

Still broken, working on it.


More fine web graphics resources:
Copyright 1997 jim barchuk
jb@jbarchuk.com
URL: http://www.jbarchuk.com/cgm/