Middle-Fork

You have the image reversed. I just downloaded a copy & then flipped it around. Now the tracks look like impressions.

This is an example of relief reversal:
http://snailstales.blogspot.com/2005/10/relief-reversal-effect.html

The image is as I took it. There was strong late afternoon sun from my right.

Here's the original, merely resized:

http://www.middle-fork.org/archives/dPrintsa.gif

Perhaps I don't understand what you're saying. I'm familiar with the effects of positive and negative relief and their shadows. Perhaps my impressions of this image are spoiled by the vivid memory of the day, and of finding the prints. For size, you can see one of my footprints above the log. That's a size 8 human print.

Maybe I increased the contrast too much.