Well, it's actually half rhodium, half gold. Rhodium won't print out alone even with my ammonium ferric ferrous oxalate formula. But it will behave itself if "seeded" with gold or, I assume, palladium. It's pretty much the same as my Karytype formula -- gold and platinum -- except you can go a little higher, half and half, with rhodium before you need to start adding 26% ferric oxalate to boost contrast. No glycerine needed because rhodium does not grain up like platinum. (The Karytype process is demonstrated in detail on my Youtube channel.) "Kary" is my personal designation for any process I invent that uses gold mixed with another metal (electrumtype kary = gold+silver, Karytype=gold + platinum).
The image is a 4x5 contact print, which is economical for developing new processes. Capture was with my cell phone camera since my HP g4050 scanner decided to leap to its death from a tabletop. The rhodium solution strength is 10%, same as the gold. Some gray-purple staining appeared when I immersed the print in a 1st bath of 1% nitric acid (to nudge it toward cleaner grays). The weak nitric acid stops further print out cold and a few alternating baths in tetrasodium EDTA and water do the rest. Paper is Arches Aquarelle, hot pressed, which is factory sized with gelatin. I love this paper. Much better results with gold than Arches Platine.
Yes, I know rhodium(III) chloride hydrate is pricey, but that's only because B&S and Artcraft don't sell it as they do gold, platinum and palladium. I picked up one gram for $170. I later found a reagent supplier selling it for more like $100 a gram. At a 10% solution I can print 40 8x10's in 50:50 Ro-Au, which works out to about $5 a print with the gold factored in. Cheaper than printing platinum and the images are rare to say the least!
The image is a 4x5 contact print, which is economical for developing new processes. Capture was with my cell phone camera since my HP g4050 scanner decided to leap to its death from a tabletop. The rhodium solution strength is 10%, same as the gold. Some gray-purple staining appeared when I immersed the print in a 1st bath of 1% nitric acid (to nudge it toward cleaner grays). The weak nitric acid stops further print out cold and a few alternating baths in tetrasodium EDTA and water do the rest. Paper is Arches Aquarelle, hot pressed, which is factory sized with gelatin. I love this paper. Much better results with gold than Arches Platine.
Yes, I know rhodium(III) chloride hydrate is pricey, but that's only because B&S and Artcraft don't sell it as they do gold, platinum and palladium. I picked up one gram for $170. I later found a reagent supplier selling it for more like $100 a gram. At a 10% solution I can print 40 8x10's in 50:50 Ro-Au, which works out to about $5 a print with the gold factored in. Cheaper than printing platinum and the images are rare to say the least!
