I've personally found the dinosaur skin impressions we've had in the lab particularly exciting. Seeing the texture of scales and scutes evokes living, breathing, and dying creatures in a way that bones alone don't do. At the Utah Museum of Natural History, we see a lot of hadrosaur skin. Mike Getty tells me that hadrosaur skin impressions are more common than for other dinosaurs. That may say something about the toughness of hadrosaurine hide. And it seems that the fossil hadrosaur sites in Utah's Grand Staircase provided especially good conditions for skin impression preservation.
Last night I did some test photography on some large skin areas with cast (positive) and mold (negative) impressions of hadrosaur skin. Scales, scutes, and skin wrinkles are recorded in sandstone. The image below is a mold impression. You can see scale texture and a row of scutes that studded the top of the hadrosaur's tail. Each scute was located above the neural spines of the duckbill's vertebrae.
I wanted to work out what kind of lights to use and how best show the skin texture. It's difficult to use a very shallow angle light and get good exposure across a large specimen. I've masked out the lab background and sandbags that support the pieces. This is a perspective view with the distal end of the impression at the top of the image. There are more puzzle pieces we can fit into place for the next photo session.