Oil and "Photographie Synthetique"
The info I found on "oil printing" is scattered and incomplete (there's clearly room for a book on the topic) but I'm going to do a once-over lightly as at least an orientation -- more or less in chronological order.
I begin with the subject line above, however, because that's the title of a chapter in this French book (which weighs more than I do, lots of tip-ins and articles by Puyo and Demachy, among others -- I traded for it, in the long long long ago). Can anyone suggest what "Photographie Synthetique" means in this context? The chapter is by Puyo, but the language is so "abstract" (no process, just theory) I can't read it, or not this late at night.
When I translated a couple of Puyo-Demachy articles for Post-Factory, seriously assisted by a French photography student who ALSO had a classic French dictionary (since these technical terms tended to be obsolete), that word never appeared. My own semi-ancient French dictionary (only 1942 or so) defines it as, simply, "synthetic" -- but experience says there's a particular meaning that fits our field and I'm hoping some French-speaking or expert bi or tri-linguist on the list will know it.
The title of the tome itself is "La Revue de Photographie, Deuxieme annee 1904," published by the Photo-Club de Paris. Before I was forced to speak Swiss German for 6 years, I could manage fairly well in French... Now I'll skip this chapter (as noted, a quick skim shows mostly abstract generalizations) and go directly to the part in the back of the book, page 391, found under "Huile" (oil) in the index.
This long single-spaced paragraph translates (very) loosely as follows:
Positive proofs in "oil":
M. H. Rawlins offers a new process for artistic printing based on the same principle as photocollography, which he described in "The Amateur Photographer."
He covers a sheet of paper ("a dessin" -- don't know what that is, and can't put the accent on the "a') with a coat of gelatin, of medium consistency, and insolublizes the coat with formalin and sensitizes by floating in a potassium bichromate bath "21 / 20 / 0" (whatever that is). After it's dried in the dark, the gelatin side is exposed to light under a negative, which gives a weakly visible image. It must be blotted ("poussee"?) until the details in the highlights are weakly ("accuses" = visible?), several times in hot water until the image relief is weakly visible. The paper is then washed to remove all visible traces of the bichromate in several baths of hot water, until the image relief is accentuated. Then you put it on a thick (oh what the hell, what is "une epaisse feuille de glace" -- a thick sheet of ice???) and roll on the ink with an inked up roller. Or you can ink with a brush and change the values either completely or where you want. Moreover, if the image doesn't satisfy the artist, it's possible to clean it off entirely with terebenthine, and start over.
Or just clean off parts. M. Rawlins also uses solid oil colors invented by Raphael. He says the skill with which the artist creates these tones equals the skills of an oil painter, without losing the underlying image in the gelatin. The examples with his article show a certain timidity (who? what? inconnu!)...
The item goes on to claim that, unlike gum, which is "irremediable," oil printing can always have a new "encrage" (not in my dictionary, maybe "inking"?), but I pass on the last 2 or 3 sentences, fearing that I've already invented enough.
Which is to say, OK, I've done some guessing, for which please forgive, but that's definitely the gist.
PS: I thought it was in the French book, but don't find it now, still I mention while I think of it: One of these old books, in an article on tricolor gum printing, begins with CYANOTYPE for the blue !!! (Hi Sam: are you there?!!!)
I thought that was a modern invention, but it was, if not 1904, no later than 1908 !!!!!