in your situation, I would take a flashlight and shine it on the workpiece, look at it from various angles, notice the play of light and shadow.
you could even work with the reflections off the surface. use it like a mirror. bounce some light off the workpiece and against a wall or sheet of paper. assuming the surface is supposed to be smooth, wherever the reflection is dark is where the surface scattered the light instead of reflecting it evenly.
some of that is bound to make a useful picture.
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