The effect of the Iterations Parameter

Pixels in the images are coloured according to how many iterations, i, are required before the magnitude of Z becomes greater than 2 (|Z_i| > 2), or alternatively Zx² + Zy² > 4. If Z hasn't diverged complex numbers, so we really mean |Z₂₄₀₀| < 2. If |Z| becomes greater than 2, we count the number of iterations that have passed and use this to choose a colour. If, after we've iterated more times than we care to, we still haven't passed 2 we assume the point is inside the set and colour it black. If you try generating your own patterns you will find that the further you zoom in the larger iteration cut-off you will need to draw decent patterns. The following two images illustrate the effect of changing the maximum number of iterations from 16 to 2400. In this case 2400 is probably too many, but 16 clearly isn't enough. If you choose too many the image will take ages to draw but otherwise will be ok.

16 iterations	2400 iterations

These pictures also illustrate the advantage of the new colouring algorithm. The locations of the colour bands no longer change depending on the number of iterations, so if you want to create a series of zoomed images you can increase the number of iterations as you go without loosing continuity. They were created with the new "-d8" colour scheme

A large image (it's 5000x3750 pixels!) created using the d8 pallete.