Reverse Engineering Circuit Boards with White Soldermask

[electronupdate]

Recently I was looking at a circuit board with white solder mask (extracted from an LED light bulb).  The trouble with white (and black) solder masks is that they are opaque which complicates circuit tracing.  The green solder masks are somewhat transparent.... but these white and black ones really hide the traces.

One technique I have been having quite a bit of success with is using the free general purpose photo editing program called "GIMP".  Their is a subtle difference in color of the solder mask over a trace which can be accentuated using the color --> curves function in the program.

Video here which shows how details can be teased out of a photo:

http://youtu.be/y3gf2DHwzhY