THE CHRYSOTYPE SUPREME
In 1854 Robert Hunt published a process with which he coated paper with an iron-based light sensitive chemical, exposed a glass negative in contact with the paper, and then washed the weak image that subsequently printed out with a strong solution of gold. While the images so produced exhibited the highest quality of any photographic prints at that time, Hunt's process never attracted a following, presumably because of the expense and the purple color. A variation on that process, the so-called "Chrysotype Rex", was revived early in the 21st century. In the "Rex" process, the printer exposes a weak image on ferric oxalate and then washes that with an 8% solution of gold chloride. Bottom line: Hunt's process yielded higher quality. But, then, Hunt was a genius.
Late in the 20th century, Richard Sullivan announced a variation on his Ziatype formula in which he substituted gold for the lithium palladium. The gold images so printed are coarse, contrasty, and red. Ten years later, a Scottish university don -- the same one who preposterously claimed to have invented the glass coating rod -- announced a chrysotype process that was essentially Sullivan's formula with the strength of the gold solution roughly tripled. The "New" chrysotype proved unsatisfactory for true pictorial photographic images, limited as it was to a range of approximately 6 or 7 steps from its weak blacks to blown highlights.
In August 2011, Richard Eugene Puckett took an entirely new (and finally successful) approach to printing photographic images in gold. That approach is the Chrysotype Supreme. The principle underlying the Chrysotype Supreme (and the Platinotype Supreme, Palladiotype Supreme, Rhodiotype Supreme, Auridiotype Supreme, Karytype Supreme, and Iridiotype Supreme) is that replacing the ferric iron in a light-sensitive double ferric oxalate/citrate/tartrate with a compound iron, ferric-ferrous iron, initiates reduction of the nobler metal sooner, with faster and thorough image-forming. Ammonium ferric-ferrous oxalate, or other double ferric-ferrous oxalates, or ammonium ferric-ferrous citrate eliminate the need not only for development, but also for the old 19th century technique of paper hydration. The photographs are distinguishable from platinum only in the slight to significant color cast to the image. That color is controlled by the dampness or dryness of the paper; a print made on fully dry paper is generally gray scale, like platinum. If the sensitzer was slightly damp, the image usually takes purple case; with very damp sensitizer, the image usually takes a red cast. A pink cast, with obvious grain, (which a printer in Australia speciously calls "blushing chrysotypes") is obtained by adding a small amount of palladium to the gold and printing with very damp sensitizer. The printer controls contrast in three different ways: selecting a more or less contrasty iron compound, as appropriate, or by mixing either of two double ferric oxalates with ammonium ferric citrate, or by varying the number of drops of ascorbic acid added to a known volume (strongly suggested as 10 ml) of the iron compound.
The essential formula for a Chrystoype Supreme requires the following chemicals:
- distilled water
- gold chloride
- ammonium ferric oxalate
- sodium ferric oxalate prepared from raw materials (Richard Sullivan in the Articles section of www.bostick-sullivan.com provides a simple formula: in a container for at least 200 ml dissolve 3.9 grams of oxalic acid and 5.7 grams of anhydrous sodum carbonate in 40 ml of warm water. Slowly stir into the solution -- with a great fizzing as carbon dioxide is released -- 6.9 grams of ferric oxalate. Gently warm the solution, while stirring, until the solution turns clear but dark green).
- ascorbic acid
- muriatic (hydrochloric) acid
- sodium sulfite
Prepare the solutions of the above as follows:
- Wear rubber gloves and a splash mask when handling gold chloride as it is highly toxic (read "poisonous").
- Dissolve 1 gram of gold chloride (tetrachloroauric acid) in 8ml to 10 ml of distilled water at 80 to 90 degrees Fahrenheit. (Any solution stroner than about 12% is a waste of gold.)
- Pour the gold chloride solution into a brown glass bottle with an eyedropper and label it as Gold Chloride, notng solution strength.
AMMONIUM FERRIC OXALATE
Ammonium ferric oxalate can be problematic. I used the same large container of the chemical from 2010 to 2018. When that supply was finally exhausted, I ordered fresh ammonium ferric oxalate and discovered, to my horror, that my formula no longer worked. The quite new batch was useless. I experimented with different methods to "reanimate" the stuff but without any success. Platinum and palladium prints were far too contrasty and gold worthless -- no matter what I did to the chemical! I had to resort to preparing my own sodium ferric oxalate (below) in order to be able to print! I finally ordered a new supply of ammonium ferric oxalate in late 2019, over a year later, and to my joy the new batch worked perfectly. Lesson learned is, if your ammonium ferric oxalate does not behave as specified, switch to sodium ferric oxalate until a fresh batch is available from Artcraft Chemicals.
- Dissolve 4 grams of ammonium ferric oxalate in 10 ml of distilled water at 80 to 90 degrees Fahrenheit.
- Pour the 40% ammonium ferric oxalate into a brown glass bottle with an eyedropper and label it, including date of preparation.
SODIUM FERRIC OXALATE
As an alternative to ammonium ferric oxalate, prepare 40ml of sodium ferric oxalate according to Sullivan's formula. Note that the solution is easier to prepare than ferric oxalate by itself, which can be time consuming and tedious to get into a clear solution.
- Pour 20 ml of the solution into two separate bottles labeled and dated.
- Add 3 drops of 1% ascorbic acid to one bottle of 20ml of sodium ferric oxalate and note that volume of C on the label. Shake the bottle vigorously for at least 15 seconds to mix the two solutions. Use the solution in this bottle to print contrasty negatives in gold.
- Add 6 or 7 drops of 1% ascorbic acid to the second bottle of 20ml of sodium ferric oxalate and note that volume of C on the label. Shake the bottle vigorously for at least 15 seconds to mix the two solutions. Use the solution in this bottle to print normal -- lower contrast -- negatives in gold.
- Dissolve 0.1 gram of ascorbic acid (raw vitamin C crystals) in 10 ml of distilled water. Sodium ascorbate may be substituted: ascorbate is merely buffered vitamin C.
- Pour the 1% solution of C into a brown glass bottle with an eyedropper and label it, including solution strength.
AMMONIUM FERRIC-FERROUS OXALATE
- Count 3 to 8 drops of the 1% C solution (3 is low contrast, 8 is higher contrast, with 6 drops recommended as a starting point) into the bottle containing the 40% ammonium ferric oxalate. Recap both bottles.
- Vigorously shake the ferric compound with the C for at least 15 seconds.
Wear rubber gloves and a splash mask when handling muratic acid. Handle the acid out of doors with a cold water hose at hand with water running from it.
- Pour 2 ounces of muriatic acid (~31% hydrochloric acid) into 62 ounces cold water. Label the container used.
Assemble the necessary tools:
- A soft, synthetic brush at least one-quarter the width of the area to be sensitized. For example, a 1.25 inch brush suffices for sensitizing the area for a 5x7 negative.
- A shot glass or other small glass vessel.
- A contact print frame.
- A tray or trays one size larger than the paper or fabric on which the contact print is to be made.
- UV light source (sun, UV fluorescent lamps, UV LED bulbs, etc.)
- Paper: Arches Platine hot-pressed, Arches Aquarelle hot-pressed, Bergger Cot 320, Legion Revere Platinum, Clearprint 1000H rag cotton vellum
The printing process is simple:
- Mix the gold chloride and the ferric-ferrous oxalate (ammonum or sodium) being used into the shot glass. The ratio of gold to oxalate is 4:3. In other words, for a 4x5 print mix 4 drops of gold with 3 of the double ferric-ferrous oxalate solution. Use 16 of gold and 12 of the oxalate for an each for an 8x10 and so forth.
- Swirl the solution to mix the two.
- Pour some (most) of the solution onto the paper and brush it quickly and lightly across the paper within the rectangular area to be sensitized. Note: gold is too thin to use the old 19th century glass coating rod.
- Add the remainder of the solution where needed to even out the sensitized area.
- Place the sensitized paper in a dark place to dry.
- After approximately 15 to 30 minutes, when the sensitized area is fully dry, place the paper in contact with a film or inkjet negative and place both in a contact print frame.
- When any overbrushed area darkens significantly, or otherwise after about one minute, drop one side of the back of the contact print frame to observe the progress of print out. The print is ready when it is approximately 1/3 stop lighter than desired. It will darken about 1/3 stop on drying after clearing.
- When the print has reached the desired density, remove it from the contact frame and immerse it in a tray containing a 5% solution of iced sodium sulfie. This step prevens the image from darkening.
- Transfer the print to a tray with the hydrochloric acid mixed with ice.
- Agitate the print in the tray gently for 10 to 15 minutes.
- Wash the print in running water for 30 minutes if you printed on Clearprint 1000H , 45 minutes for the heavier papers.
- Lay the print face up on a fine-meshed screen or cheese cloth to air dry.
TIP: Want a red print, similar to the so-called "New Chrysotype S"? Why? Oh, well, there's no helping some people so go ahead: With a wet brush, dampen the back of the paper behind the sensitized area and print without drying the paper.