I've noticed something interesting, and I thought I would run it past the Picnickers who are into photography. I've found that there is a distinct difference in appearance, in "tone," between the drawings I've made from photos of ordinary people, and great master painters, and the ones made from photos from modern magazines.
In learning to draw formally in a studio, a great deal of time is spent copying "from the flats," as it is called by instructors. That is, from 2D depictions of objects, usually casts of famous Classical and Renaissance statues.
Outside the studio, I have amassed a collection of art books with good black and white and colour photographs of those statues, both by the Ancients and the great Italian masters. Drawing practice from these is a great pleasure and always presents some new thing to learn and perfect. Somewhat less frequently, I also use photographic reproductions of master paintings, and making "master copies" is a big part of classical instruction.
In drawing the figure, I'm currently doing a little practice project in my book recommended by one of the online drawing people. Drawing 100 noses, 100 eyes (or pairs of eyes), 100 hands, 100 legs etc. The idea is to become so familiar with the structure of these that they become almost automatic, so when drawing from a live model I can cut down on the time it takes to produce a likeness. It's quite fun actually, and I might put a few up and make a contest out of it: "Name that nose".
I've always known that a lot of drawing practice involves copying from flats. Everyone used to start off with the Bargues, a set of lithographs, and so we still do. And I am given to understand that in some places (that should know better) all the drawing instruction that is offered is the kind that involves taking a page out of a magazine, drawing a grid on it and copying from the grid. But this latter always seems to produce a much inferior quality of work.
As well, for some years I thought a convenient way to learn figure drawing, at least to learn the basic human proportions, would be to practice using photos from fashion magazines. They may not help you produce great art, but at least you could become adept at rendering the human form, correct proportions, etc. But now, having tried it a few times, I find that there is something about most fashion photography that produces a strange quality to the drawings. I suppose it is true that you could use fashion photos effectively, if you had no other source (living on, say, Mars) and wanted to learn to render the figure. But they have such an air of unreality about them that the drawings have an oddly unnatural feel. I don't know how to describe it better than that.
What I was wondering about, and would like to hear from our photography readers, is what about that kind of photography produces this strangely flattened effect.