Sterling Fractal

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Fractal image with colouring algorithms generated by Sterling Fractal

Sterling Fractal is a freeware fractal-generating program by Stephen Ferguson, a programmer and mathematics hobbyist. The program is downloadable at no charge, with source code available for modifications (see the external link at the bottom of the page).

Originally Sterling Fractal and its cousins, Tierazon, Iterations, et Flarium, did not cost anything. The programs were given away as public domain, with source code. But sometime in 2003 or 2004, the author removed free copies of these programs and put them on for-pay download sites. It is still possible to find sites with free copies of the programs, but such sites are currently rare.

[edit] Focus of fractal generators

The image above and to the right is a plot of the standard Mandelbrot set, however, there are filters in place that add interest to the image. The dark green and pink regions in the upper right are areas that are not part of the set, and traditionally is where much of the colour banding occurs. Notice there is no colour banding, rather, sweeps of colour.

The light blue and green region on the left and lower left of the image are areas that are part of the set, and traditionally the colour there is a single, flat monochrome. However, the colour filters have added banding and sweeps in that range, adding interest to what would otherwise be a very boring segment of the image.

$A non-Mandelbrot fractal rendering.$

A non-Mandelbrot fractal rendering.

The image to the left is another non-Mandelbrot fractal, but since the main focus of Sterling Fractal is the colouring and filtering algorithms, this fact will not be apparent except to the most ardent Mandelbrot-exploring aficionados.

In traditional generated images of fractals, the majority of the interest lies only on the boundary between the points that are in a fractal set and the points that are not in the fractal set (with additional interest in how far from being in the set certain points are).

Sterling Fractal, however, is based on the belief that filters and colouring algorithms, rather than the actual fractal boundaries themselves, hold far more interest in creating a visually-appealing representation of the fractal set. The fractal merely serves as a seeding function to the colouring algorithms and filters.

Traditional rendering of the Mandelbrot set.

The image to the right is better for understanding what pixels lie within or without the Mandelbrot set due to the less-interesting colouring. The area that's within the set is the completely black region in the lower left, and the completely black "dots" within the red areas. What is not in the set are the coloured reddish regions that fade to black toward the upper right. Programs like Fractint, which use the traditional iterative colouring methods, are much better utilised for understanding and learning about Fractals, whereas programs that have complex filters are better for producing beautiful pieces of art.