Only possible with ammonium ferric ferrous oxalate, the "magic iron" of my dream almost three years ago made reality. This giant image is formed from elemental gold, deposited on the dry paper with the surfeit of ferrous iron in 36 ml of ammonium ferric ferrous oxalate mixed with 24 ml of 10% gold chloride.
The negative for this print was an inkjet transparency, prepared with tremendous dedication by Bobby Valentine of GicleePrint.net. Bobby tolerated my destruction of the first negative trying to wet mount it on a sheet of 3/8" acrylic, and my obsessive-compulsing over two further negatives before he riddled out what the hell it was I wanted in my negative.
The frame was a simple construction with a sheet of acrylic glass and 9 crossbars held on with gate clamps. Fifteen corks on 2" screws allowed me to adjust the pressure precisely on the back of the paper, keeping it from pulling away from the negative. Instead of wet mounting, I simply stretched paper and negative taut and taped each separately against the acrylic.
Clearing started in a 10' diagonal wading pool in my dim workroom and finished in my bathtub. I furiously drained and refilled the tub, mixing in at different points: bleach, nitric acid, dithionite, tetrasodium EDTA, and hydrochloric acid (it's one clean tub now!).
The subject is the most sacred building in the western hemisphere: The Alamo. (Photo Credit: Kary)
MAJOR UPDATE TO THE TEXAS CHRYSOTYPE: THE RIGHT PAPER FOR THE RIGHT RESULTS
Consequent to a shortage of Arches Platine, I reluctantly resorted to printing gold on Arches Aquarelle hot-pressed paper, which is sized with gelatin. Seeing the tremendous quality of Electrumtype Kary images, I printed a Texas Chrysotype using 10% gold, and AFFO prepared with 7 drops of 1% C added to 10 ml of ammonium ferric oxalate. The printed out image was purplish-brown, sufficiently deep in tone as to appear warm gray and warm black. The overall quality is comparable to a platinum print. On a hunch, I mixed up a weak -- 1% -- solution of nitric acid. I immersed a print (3 drops of Au/3 of AFFO-7:1%C) in a first bath of that 1% nitric acid. Almost instantly, the image turned gray, with some purple/dark lavender staining.
The smoothness of an image can be even further enhanced by reducing the number of drops of 1% ascorbic acid added to 10ml of 40% ammonium ferric oxalate. As few as 3 drops of C can be used. If a contrast boost is desired, 26% ferric oxalate serves perfectly without graining. Conclusion:
By printing gold on hot-pressed gelatin-sized paper you can print Texas Chrysotypes largely distinguishable from platinum only by some purple staining (usually near the edges of the image area). You can alter the tone of the image with a very weak nitric acid first bath: you may or may not find this step desirable. Clearing is the usual water/tetrasodium EDTA/water/sodium sulfite/water/tetrasodium EDTA/water sequence. The gelatin seems to want to hold the iron in, so you may need to use a stronger (double-strength) and longer sodium sulfite soak. If for some reason that does not suffice, an overnight bath in 7% tetrasodium EDTA and 2% sodium dithionite will clear the iron from anything. I have not needed this, yet; a strong sodium sulfite bath has sufficed to clear yellow staining.
Arches Aquarelle is gelatin-sized in the factory and is both more readily available and less expensive than Arches Platine. Further, you can purchase hot-pressed Arches Aquarelle in rolls as wide as 51". Combine the above Texas Chrysotype formula with Aquarelle and with a 3000 DPI drum scan from an 8x10 FP4+ negative and a 4'x5' inkjet transparency made with an Epson 11880 or other wide format inkjet printer and gold prints finally are ready to astound the world with their beauty. (Tip: you'll need to construct a really, really, large and heavy contact frame.)
Kary with Martini Glass, 4x5 Texas Chrysotype, AFFO-7:1%C, on Arches Aquarelle.
Sizing paper with gelatin
There are many superb papers you can size with gelatin:
- Arches Platine
- Revere Platinum (both light and heavy versions
- Clearprint Rag Cotton Vellum
- Bergger Cot 320
The primary consideration is that the paper have a hard, smooth yet still fibrous surface, in other words, hot-pressed.
The only materials you need for sizing are a tray, Knox clear gelatin (available in the baking and/or jello section of any large grocery), and an optional hardener (alum, chrome alum, glyoxal, or formaldehyde).
You can buy my manual for the formula or you can read section #3 in Jill Enfield's excellent article on sizing/subbing papers, totally free (I would post the information here, but it is from copyrighted material): http://www.alternativephotography.com/wp/paper/sizing-or-subbing-papers