Portrait of a Dog

Portraits have never been my forte so I keep practicing, this time with a dog. I worked from a photo of this Labrador German shepard, which is my daughter's boyfriend's dog. I don't know the dog personally, so I wish I had a better picture, or at least a couple of different reference photos to better determine his coloring. Being a mostly black dog makes it challenging. The highlights in the photo come off as white and every shade in between, similar to my experience with my drawing of Darth Vader. This time, though, I was working with watercolor and fur.  I think I did a good representation of the dog that is in my reference photo, but I'm not sure if the reference photo accurately represented who the dog is.