The slight coloration is a marvelous, subtle touch that adds greatly to the cartoon. Sepia: 1. a reddish-brown color associated particularly with monochrome photographs of the 19th and early 20th centuries. I really love this comic!
Funny, but I think there is an issue with light and geometry here. By reflection, he should see danger coming from across the stream, in front of him. But I can see why that would be an awkward way to make the point.
Yes.