I wrote about Groesbeck here. A Muddy Colors post dealing with him is here, and examples of his work done in Siberia and East Asia is here.
The images below are a supplement to the better works I posted earlier. Most are related to movies. Still, they are worth a glance.
Perhaps the best work in the collection above.
This painting was cleaned a few years ago, but most Internet images are of the pre-cleaned version. Here I used the tools on my iMac to simulate the cleaning. (The darker version can be seen on the link above to my earlier post.)