Here is another color comparison. This little dog was painted close to the values of a photograph I had altered to decrease the shadow of the little guy's face in a client's photo. However, as painted (left) the client hoped to have the shadow side even lighter than this. Because values are related on the lit and shadow sides of an object, I decided to re alter the photo, further increasing the exposure and then repaint.
Here is the lighter painting with a lighter background. This version felt better to the client.
To me, this is another interesting effect of color and how color creates a feeling: scruffy, rambunctious or refined and trimmed. I am working on a series of crows. A dark background makes them more menacing. I'll share this soon.