Psuedo High Color "PHC"
and
Psuedo True Color "PTC" Fractals

A tutorial by Sylvie Gallet
version 2.0
May 1997





This document is Copyright (c) 1996-1997 by Sylvie Gallet. I encourage you to copy and distribute it, so long as you leave it unchanged. It may NOT be used for commercial purposes without my explicit prior permission.

Any comments, questions, corrections... are welcome. My addresses are:

             CompuServe:  Sylvie_Gallet  [101324,3444]
               Internet:  sylvie_gallet@compuserve.com

Pseudo-HiColor (PHC) was co-discovered by Jim Deutch who wrote the very first PHC formula and Lee Skinner who realized the enormous possibilities that this technique offers. Given the great interest aroused by PHC, the Fractint developers decided to implement three new variables that make formulas much simpler; a big thank you to Tim Wegner, Jonathan Osuch and George Martin for doing this!

And a MEGA thanks for the IF..ELSE instruction they implemented in Fractint 19.6. This very powerful instruction considerably improves the readability of the formulas that use conditional statements and makes them generally faster.

In this second version of the PHC and PTC tutorial, I have rewritten both the explanatory material and the formulas to take advantage of the express branching instructions available now with Fractint 19.6. Some historical perspective may be helpful. Branching instructions have evolved from the technique described by Bradley Beacham in his formula tutorial, to the more direct conditional assignments commonly seen now, to the new IF..ELSE instructions. PHC formulas originally contained rather complex calculations to achieve the checkerboard effect required, but were much simplified when the "whitesq", "scrnpix", and "scrnmax" predefined variables were added to the formula parser.

Because of these developments, the same PHC formula may be found in different formula files with much different instructions, depending on the "state of the art" when the particular version of the formula was written. I have included samples of formulas written in the previous style in the accompanying phctutor.frm. This should help the Fractint user to understand how the old formulas worked and make easier the conversion of existing formulas written in the prior old formats.

Pseudo-TrueColor (PTC) is an extension of the PHC concept. All the PHC and PTC formulas included in this document are by the author of these lines. Thanks to Lee Skinner and George Martin for their help, suggestions and encouragements.

The text-only version of this tutorial is also available for downloading



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