|Odilon Redon Le Buddha 1895|
I found another image, stronger if anything, of an etching called 'In teh shadow people are weeping and praying surrounded by others who were exhorting them'. This seems to have been an illustration from a book about the Tempatation of St Anthony. I cannot reproduce it here, but here is a link to a clear image of it.
It is possible to see from this image that the deep atmosphere and ominous feeling are created by cross-hatching lines. The light only lightens the shadow in one area of the prison, the rest of the people being left in darkness so their features are not distinguishable. The cross-hatching not only gives the tones, but the impression of something texturing the darkness. This is particularly effective on the floor, which not only has a graduation of light and dark within the shadow, but also the variations due to the texture of the floor. And in the background, more figures, who are so dark that we cannot be sure whether they are people or something else.