Eddie didn't need no stinking diagram. I think, put the sun behind your head...move head...take picture. My best guess.
the light is parallel to the lens not an angle down to the subject or from the side at an angle, but straight on ...
if he used a bulb flash on his SLR, he probably removed the flash from the side mount and held it across the top of the camera above the bellows to the subject.
there were papers back then that had graphite like tones ... some of ilya1963's azo prints have that same look to them .. really beautiful stuff.
You guys crack me up with the "oh there are no good papers available now which are capable of what they had back in the day" stuff.
usually the flash attached to the side ( at least with super d's i see images
with side mounted flashes ..
like the graflites on the speed graphic ... same orientation .. )
but my guess is he held the flash over the lens plane ..
but who knows, i certainly have no idea what he did or how he did it, its just a guess :)
and rendered differently. the portrait lady i worked for used to tell me that some papers had a tooth to them ...
so if areas were too dark you could abrade them with fine grit sand paper and even rub graphite into the emulsion ...
i've tried to do that with every paper i have had since 1988, and it didn't really work ...
not better, but different ...
Also, can someone enlighten me as to what he meant by - "My best work is more analogous to architecture and sculpture than to painting. I made a posterior view, in flat, but very brilliant light, which outlines the figure with such a definite black line, that even photographers swear I have pencilled the negative,--I have used this light before on the dancing nudes."
Surely if you pencil the negative, you produce a white line when printed, not black.