Wednesday, May 25, 2011

Fractal Textures

One thing that can add a lot of depth and interest to your digital pictures (and also save a lot of time), is the application of textures created by repeating shapes, patterns and forms already in the image. Fractal patterns are said to be "self similar", meaning that they are comprised of smaller versions of themselves.
With natural forms, rather than laboriously paint a bunch of little bumps and gullies, or use some generic bump texture, it can be very effective to simply create an overlay texture on the fly by reducing and repeating the overall form of the element to be textured.

Here's a basic painting of a rocky outcropping (click on any image for a larger version).

Basic rough painting

First I selected and copied as much of the rock as possible, scaled this piece down quite a bit, then pasted it all over the place on a new layer. The resulting texture looks something like this:

Rocky cliff sampled, reduced and repeated to create a texture

Next I applied this as an overlay layer above the main painting layer, and reduced the opacity a bit. This is the original rough painting with the texture over it. Even though the texture clearly repeats when viewed in isolation, this is not apparent when it intersects the larger, similar forms of the main painting on which it's based. Quite the contrary, in fact, the illusion of entirely new forms is created:

The two combined

If the texture layer's opacity is too high it looks cool, but may tend to flatten out the underlying big forms, or its repeating pattern may become evident: 

Too much texture?

Fine tune areas of the texture that aren't working well by touching up with the rubber stamp tool, sampling other areas of the texture, and add a layer mask to control precisely where the texture is applied.