The Basic coloring algorithm implements four simple and classic ways of coloring the outside areas of a fractal. It is useful for reproducing fractals created with older fractal software.
The Coloring Type parameter selects how the fractal should be colored:
The Iterations option colors a pixel according to the number of iterations that were necessary for the fractal formula to bail out (to decide that it’s an outside pixel). This is the oldest method used to color fractals. It creates images with bands of solid colors. To smoothen the bands, use the Smooth (Mandelbrot) coloring algorithm.
The Real, Imaginary, and Sum options use the last value of z in combination with the number of iterations to color pixels. They create smooth, true-color images. Good results are usually obtained if the bail-out parameter of the fractal formula is not set too high. Try 4, for example.