This effect was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
A filter that attempts to mimick explicit OpenGL blend modes.
The premise is best explained here...
http://www.modw
For the most part it's useless. It's really just for demonstration.
I haven't implemented alpha channels as there wouldn't be much point unless I could reference a second image.
OpenGL explicit blendmode add filter modulate blend
This filter has earned its author one of our rewards. They are given to the authors of popular filters and include a free copy of Filter Forge.