What kind of processing is this?

I think it's a different type of painting with light than you are thinking of???? Check out the following link:

http://www.atncentral.com/developer.html

and look at PWL & PWL II photoshop actions (the R-S section , items 22 & 23).

These can be used for very large areas.

--
A Few Images ... http://www3.sympatico.ca/gord.lange/a_few_images/