In reply to the challenge in Draconian's excellent tut "How to make pitted metal- Metal Wurx XV".
To me, and all of these are amazing pieces and an amazing tut, but they all still lack one thing about pitted metal. When on a 3D object the "pits" should appear to affect the shape of the object, not just appear on the surface of it. Kinda of like a rock that has been struck by many an objects (sometimes I don't even know where I get these references) it alters the way the light effects each individual area, which I think is what is the one key part to any digital attempts. If we could somehow figure out this and how to replicate this I think no-one would really be able to tell whether it is real or not....get my drift?
I think you have a valid point and it got me to thinking. If maybe we split up teh "pitted" layers somehow and did them at different depths on the bump map, the resulting lighting effect fo the bump would render the difference you are looking for. I'll have to experiment with that to get more randomness that makes it look more realistic or did I mis your point?
Did you mean the overall shape of the beat up metal? If so, maybe warp it or create a warped shape and use Filters>Map>Displace like you might do with water ripples. Just tossing out ideas. Let's see if someone can come up with some examples to look at so maybe we can "see the layers" in the image and perhaps replicate it. Do yo have an image in mind?
An interesting challenge. I took some photos of an old 6x4 trailer that was originally deep blue but the sun and rain had got too it and it is rusting away.
The original photo is washed out a bit and the simulated image is closer to the real colours.
This took me five hours or so to do. It is not easy the first time as you are feeling your way at each step.
I submit part of the original photograph and a gimp image produced entirely within Gimp with basic filters and controls to try and simulate a convincing rusted, pitted, sun bleached rusty panel. I hope that someone else takes up this challenge as well. NO imports of any images to use as templates, patterns or backgrounds allowed.