Drawing and photography are radically different ways of making pictures and the pictures that result are not equivalent or interchangeable. The short explanation is mildly abstract. Please forgive.

Drawing belongs to a class of picture production methods in which a mark-making "device" is directed by a set of coded instructions to lay down a bunch of marks on a substrate. The bunch of marks is the picture. Practically speaking, the mark-making device is, of course, the artist's hand with a pencil in it and the set of instructions reside in the artist's brain. If the artist has paint and brushes in hand the result is a painting. And if the artist's brain is replaced by an electronic brain and his hand is replaced by an ink-jet printer then the result is a digital picture. Yes, digital picture-making is just a fancy robotic version of good old drawing and painting.

There is another class of imaging methods which do not use mark-making devices or coded instructions filed away in one brain or another. These methods depend on direct physical contact or direct physical sampling between subject and image. Examples include footprints, wax impressions, life casts, death masks, brass rubbings, silicone rubber moulds, coal peels, and photographs.

Drawings and photographs have a fundamentally different relationship to subject matter and offer a different experience to the perceptive viewer. To the non-perceptive viewer "looks like" means "same as" and no mildly abstract thoughts need be entertained.