Using Color Maps
WHAT ARE COLOR MAPS?
In most computer systems, colors are stored in RGB (red-green-blue) format. In total, there are 16777216 different colors in this system. Most pictures, including fractals, however, only use 256 colors. The colors are numbered from 0 to 255, and to each of them there is an RGB number assigned. The table in which these numbers are assigned is called a color map. The coloring of the fractal completely depends on the color map you are using. While creating fractals for this website, we have experimented a lot with coloring them, for the purpose of which we had to use and create different color maps. Most of the following tips are based on some of our own experience that we would like to share with you.
TYPES OF COLOR MAPS
Although the usage of color maps depends completely on the situation, there are several generalizations that you can make about them. We tried to break up all color maps into several categories depending on their "structure". Since color maps with the same structure create similar effects, it makes it easier to give general information.
1. Smooth Maps create a smooth transition from one color to another.
2. Darkness Transition Maps create a smooth transition from black to some color of vice versa.
3. Gap Maps same as darkness transition maps, only with several consecutive transitions. They can have several different colors in them with black gaps in between.
4. Pattern Maps a series of several very distinct colors repeating itself many times
5. Unpatterned Maps all colors are different with completely no patterns
6. Natural Maps the coloring is intended to imitate nature and can have any of the above patterns
Beauty can be very rarely achieved by using a color map with too many unpatterned colors that are much more likely to hurt your eyes. When the only goal you are trying to achieve using coloring is beauty, the best color maps to use are ones that have very smooth transitions from one color to another (see types 1 and 2). The pictures below show this concept. As you can see, when the shape of the fractal itself is beautiful, smooth coloring only perfects it.
The human eye usually percepts light colors to be closer than dark ones. When you are trying to give a fractal 3D effects, it is a good idea to use color maps that have smooth transitions from black to some light colors (see types 2 and 3). When there is more than one black spot in the color map (see type 3), it is often capable of creating black color on both sides of a light spot, which creates the best 3D effects. The picture below shows how an ordinary figure can be turned into a very 3D looking one using a darkness transition map.
When you are using any smooth transition map, neighboring colors are too similar to each other to be easily distinguished from one another. Sometimes, however, the fractal contains shapes that give it a special look if they can be easily distinguished from one another. In such case, smooth transition maps dont work and the best maps to use are maps with completely distinct unpatterned colors (see type 5). The picture below is the "Mice" fractal. The colors of the mice are very close to each other, and when a smooth transition map is used, it is impossible to see the separate mice. When, however, an unpatterned map is used, the separate mice can be easily seen.
Smooth transition maps are capable of using different shades of the same color throughout the fractal. Unpatterned maps are capable of distinguishing separate shapes. Sometimes, however, you would like to have a color map that can achieve both, the same coloring and shape distinction. In such case, the best color maps to use are the ones that repeat a certain pattern (see type 4). This way, the neighboring colors inside the pattern are different, and yet the same colors repeat. In the top pictures of the example below, we have used a smooth and an unpatterned map. Shape distinction is impossible in the first example, while the coloring in the second one does not create any nice effects. The example below uses a pattern map. As you can see, it created a very nice color design, still allowing to distinguish between the different "chunks" of the fractal.
Many fractals are capable of looking like natural objects if appropriate color maps are applied to them. In order to create a natural color map (see type 6), it is best to use a real photograph that was scanned in. Programs like Fractint will allow you to automatically create a color map from an image. After we have done this with clouds, we were capable of turning fractals into clouds like in the picture below.