The difficulty in drawing from a photograph is knowing what to omit. The photograph contains too much information and generally too many contrary sources of light. Drawing from a photograph is a matter of selection and editing. Degas used photographs in an appropriate way. That is to say, he was not dominated by the material contained in the photo, and felt free to depart from it at will.

Illustration means to shed light on, or to make clear. Drawing suggests the idea of revealing something that is contained within an object and can be drawn out, rather than something that is on the surface. This may explain why those who begin to draw often start with the bones. Both activities require intelligence, perseverance, and talent.