If I had known someone would ask I would have taken notes!
Using, as always, The GIMP, and according to the best of my recollection:
1. Rotate and crop
2. Adjust levels
3. Duplicate base and disable original (for later use)
4. Duplicate active base to make a contrast layer (desaturate, invert, blend in "overlay" at 50%)
5. Merge down
6. Adust curves (standard "S" curve; up on highlights, down on shadows, midrange unchanged)
7. Duplicate active base and blend in "Grain Merge" at about 60~70%
8. Duplicate active base, move to top, invert, blend in "Divide" at about 60%
9. Duplicate original base, move to top, enable view, desaturate, blend in "Darken only" at about 60~70%
10. Scale the "Grain Merge" layer two pixels smaller vertically and horizontally
11. Scale the "Divide" layer two pixels larger vertically and horizontally
12. Merge all visible layers
13. Unsharp mask (radius 5 pixels, amount 0.5 pixels, threshold zero)
14. Bump map at 3 pixels
I
THINK that's what I did. The "Divide" layer may have been something else; I really don't recall.
I have to thank Ben for the idea about scaling layers. He mentioned shifting them, one vertically and one horizontally, and also only mentioned a 1 pixel scaling, but I usually drop the shifting and sometimes go 2 pixels instead of 1.
This is the original version:
If anyone wants to play with it and post to this thread whatever they come up with by post-processing it that would be just fine by me.