Figure 7.1. Blue Hornet’s Nest, classic and new cyanotype combined (swc), 5″ × 7″ © John P. Jackson 2018
Figure 7.2. Kristen Veiled, classic and new cyanotype combined (swc) © Sam Wang 2018
In 2017 when Sam Wang, John Jackson, Sandy King, and I began testing cyanotype formulas and sharing information back and forth, Wang was using a 50/50 mix of classic cyanotype and new cyanotype which he called CC/NC (and we jokingly called swc). It wasn’t anything he had read about doing; he was just thinking outside the box and responding to his intuition to do so. One of the hallmarks of an artist, which Sam is, is to experiment and explore even when something isn’t necessarily “done,” and to be comfortable with failure should it so arise.
Whereas new cyanotype completely replaces ferric ammonium citrate with ferric ammonium oxalate in combination with potassium ferricyanide to create ammonium ferric oxalate/ammonium ferricyanide in situ, Wang’s hybrid formula was using ferric ammonium oxalate in addition to ferric ammonium citrate and potassium ferricyanide. After Wang used the combined formulas for a while he found it to be the best of both worlds: much faster than cc, not as grainy as cc, and having a long exposure scale (ES) with softer, less contrasty highlight detail.
Figure 7.3. Spring Breeze, classic and new cyanotype combined (swc) © Sam Wang 2018
At first I didn’t pay much attention because I thought as most people do, “Why not use one formula or the other, classic or new?” Typically cyanotypists gravitate toward one formula or the other and don’t have both mixed up and on hand. Often, once the faster exposure time of new cyanotype is experienced, there’s no turning back.
However, in reviewing all my research, there were actually three formulas in the literature before 1950 that had ferric ammonium oxalate (FAO) and ferric ammonium citrate (FAC) in combination with potassium ferricyanide (PF) as Wang was doing. Two of the three formulas were probably for commercial use since they mixed up to 8 liter amounts.1 One was probably for “home use” in the typical liter amount. It seemed therefore to be on the commercial radar but not the amateur or professional photographer radar.
Though uncommon—several formulas out of 107 recorded—maybe Wang was on to something. At the very least, throughout the winter’s testing as a number of us were experiencing bouts of dendritic splotches with new cyanotype, Wang was merrily making print after print without coming across this malady.
I finally gave the swc formula a try and found it to be quite fast, on par with new cyanotype which means much faster than classic cyanotype (my exposure time is 5½ minutes, Wang’s is less). The Dmax was healthy. What seemed slightly different about the swc formula is the detail from midtones to highlights. The midtones have good tonal separation and the highlights are softer and less contrasty. There is a long trailing off of the highlights that looks like fog on a step wedge, but it is not. In looking at the exposure scale it was apparent that this hybrid formula might need its own curve. Sure enough, the calibrated curve in comparison with other cyanotype curves is very gradual and quite close to the straight line. Hence I have included its own curve in the Digital Negatives for Cyanotype chapter. What’s not to like about a deep Dmax and highlights that print forever?
Figure 7.4. Note the gradual curve approaching the straight line with minimal adjustment required for the process.
This is not to say that combining CC and NC is ground-breaking practice better than using either CC or NC alone. Each formula has its benefits and drawbacks. The point in sharing other formula practice is to encourage further exploration into the cyanotype process.
For example, John Jackson did extensive testing with swc using both 20/10 and 15/10 CC in equal proportions with NC and noted that using more FAC affects both Dmax and ES. MORE FAC gives a longer ES, a greater Dmax, and slightly different contrast. In Jackson’s opinion, there is enough difference to be a tool to use in print control.
Download and read the MSDS sheets at ScienceLab.com before using all chemicals. Exercise caution in the handling of all photographic chemicals. Use of any such chemicals constitutes some risk, and some are poisonous. The workplace should be well ventilated. Chemicals should be mixed only in the manner described. Avoid contact between the chemicals and eyes, skin, clothing, and furniture. Do not eat or drink while using chemicals. Keep them away from pets and children. Wear protective eye wear and gloves if necessary. In short, be mindful of all safety procedures for yourself and others.
You don’t have to follow these directions if you already have classic cyanotype and new cyanotype solutions at hand. Just mix classic cyanotype’s Solution A plus Solution B in equal proportions as usual, and then mix this combined amount with an equal amount of new cyanotype. In other words, 1A CC + 1B CC + 2 NC. It’s that simple.
Solution A:
20 g ferric ammonium citrate (5 tablespoons) 100 ml distilled water
Mixing Solution A:
1. Measure out 20 g of ferric ammonium citrate and add it to 75 ml distilled water and stir until dissolved.
2. Add water to make 100 ml total volume.
3. Store in a brown eyedropper bottle and label the bottle “Solution A.”
Solution B:
10 g potassium ferricyanide (2 teaspoons) 100 ml distilled water
Mixing Solution B:
1. Measure out 10 g of potassium ferricyanide and add it to 75 ml distilled water and stir until dissolved.
2. Add water to make 100 ml total volume.
3. Store in a brown eyedropper bottle and label the bottle “Solution B.”
Figure 7.5. Self Back When, classic and new cyanotype combined (swc) © Sam Wang 2018
Solution C:2
10 g potassium ferricyanide (2 level teaspoons)
30 g ferric ammonium oxalate (2 level tablespoons)
0.1 g ammonium dichromate (optional)
Distilled water to make 100 ml
1. Under low room light, place 10 g of potassium ferricyanide in a 100 ml beaker and add 20 ml water. Heat until about 160°F. Keep hot.
2. Dissolve 30 g ferric ammonium oxalate (FAO) in a separate 100 ml beaker in 30 ml distilled water and heat to 120°F until dissolved. Add the 0.1 g ammonium dichromate. [Note: dichromate may be omitted, but it helps with contrast and shelf life of the sensitizer. If dichromate is omitted, the solution last 6–12 months; if included, 2–3 years.3 If there is no scale accurate enough, make a 20% solution by mixing 5 g ammonium dichromate in 20 ml distilled water, and then add ½ ml of this to the solution.]
3. While hot, add the potassium ferricyanide solution to the ferric ammonium oxalate solution and stir vigorously.
4. Let set in a dark place to cool to room temperature and crystallize, about 2 hours or overnight. It takes a while so don’t rush it.
5. Filter the solution through a coffee filter. Weigh the crystals and observe the remaining volume of solution; there should be approximately 15 g crystals left in the filter, and about 62 ml formula remaining. If this is the case, you have done everything correctly. The crystals can be thrown away.
6. Add water for a total volume of 100 ml.
At time of use:
1. Mix one part Solution A, one part Solution B, and two parts Solution C. The new cyanotype solution should always equal the amount of combined Solution A and Solution B. 2 ml (about ½ teaspoon) of combined solution are enough for an 8″ × 10″, 4 ml (scant 1 teaspoon) for an 11″ × 14″, but mix a few ml extra to account for initial brush absorption. [Note: there are 5 ml in a teaspoon.] Wang adds 1 drop of 40% citric acid to every ml of solution to prevent highlight fog so this is an option if you have fog issues (I did not).
Wang uses an LED unit and his exposures are around 2 or so minutes. He develops his prints in a heaping teaspoon of citric acid per 500 ml water, for 2–10 minutes, followed by a 5- to 30-minute water wash.
This is for someone who doesn’t keep both formulas on hand and primarily uses classic cyanotype. All you have to add to your practice is to mix up a 15% ferric ammonium oxalate Solution C, which will require purchase of only one extra chemical, ferric ammonium oxalate. The neat thing about this quick ’n’ easy method is that you can explore varying the amount of the three solutions quite easily to see how Dmax, printing time, and color are affected. Watch how much FAO you add because the formula has a tendency to solarize. Exposure times before solarization occurs can be as short as several minutes. The solarization produces an odd etched edge effect, where adjacent to the solarizing there is a line of darker blue; this might have creative possibilities.
Figure 7.6. Note the odd edge effect of the quick ’n’ easy hybrid formula
Solution A:
Mix the 20% ferric ammonium citrate solution as directed in this chapter.
Solution B:
Mix the 10% potassium ferricyanide solution as directed in this chapter.
Solution C:
15 g ferric ammonium oxalate (1 tablespoon) 100 ml distilled water
1. Measure out 15 g of ferric ammonium oxalate and add it to 75 ml distilled water and stir until dissolved.
2. Add water to make 100 ml total volume.
3. Store in a brown eyedropper bottle and label the bottle “Solution C.”
4. At time of use, either mix equal parts of Solution A, B, and C or else vary the amounts as desired. For instance, mix equal parts of A and B and add mere drops of C. 2 ml (about ½ teaspoon) of combined solution are enough for an 8″ × 10″, 4 ml (scant 1 teaspoon) for an 11″ × 14″, but mix a few ml extra to account for initial brush absorption. [Note: there are 5 ml in a teaspoon.]
In E. J. Wall’s 1924 Photographic Facts and Formulas there were two formulas, one a 250 g FAO + 250 g PF in a liter of water. Although this formula is similar to an FAO/PF-only new cyanotype, there was no complicated mixing procedure involved where solutions had to be heated up, combined, and left to precipitate. I thought, how great, so I mixed up the liter amount and it was a disaster, as can be seen in the step wedge above. The solution was way too saturated, crystallized all over the paper surface, and produced a pale print; completely unusable. I thought to myself, is it possible Wall even tried this or just repeated someone else’s formula? For one, a single solution like this mixed up into a liter amount is equivalent to double the chemistry of a two-solution mix combined at time of use. It made me realize the reason Dr. Ware used heat and precipitation to get the two chemicals to combine and behave with one another before coming to a final mix.
Figure 7.7. Fiasco Wall formula experience. This is a picture of the 250 FAO/250 PF/1000 ml water formula that was way too concentrated and crystallized and washed off the surface, leaving a pale blue ugly print.
The other formula in Wall’s book was a combination formula of FAO/FAC/PF like Wang was doing. The formula was 166 g brown ferric ammonium citrate (the equivalent of about 197 g green), 133 g potassium ferricyanide, and 33 ferric ammonium oxalate in a liter of water. Again, I tried the full strength formula and it behaved similarly, way too saturated a formula, so I diluted it with an equal amount of water and it worked like a charm. In other words, it is best to mix up to two liters of combined solution, not one. Otherwise it produces a pale, scratchy, slow to expose, low Dmax print. Trust me; I know this because I fell for this same mistake twice.
What is the benefit of this formula over classic or new cyanotype? It is faster than CC by about ⅓ stop, slower than swc and NC by about 1 stop, but the exposure scale and Dmax rival both swc and NC and the tones are smooth. How long the combined solution will last, your guess is as good as mine, but in this user-friendly 100 ml amount you’ll probably use it up before it goes bad. The numbers are rounded slightly up, but it is somewhat like using a 20/14 two-solution cc with an added 4 g ferric ammonium oxalate to bump up the speed, Dmax, and smoothness.
Figure 7.8. Jessica in Tub, classic and new cyanotype combined (SWC) © Sam Wang 2018. Note the delicate highlight detail.
10 g ferric ammonium citrate (7 level teaspoons)
7 g potassium ferricyanide (1½ level teaspoons)
2 g ferric ammonium oxalate (½ teaspoon)
Water up to 100 ml
1. Measure out the three chemicals and add them one by one to 75 ml distilled water and stir until dissolved.
2. Add water to make 100 ml total volume.
3. Store in a brown eyedropper bottle and label as a single solution mix.
4. At time of use, measure out 2 ml (about ½ teaspoon) of solution for an 8″ × 10″, 4 ml (scant 1 teaspoon) for an 11″ × 14″, but mix a few ml extra to account for initial brush absorption. [Note: there are 5 ml in a teaspoon.]
Endnotes
1. Wall, E. J. Photographic Facts and Formulas. Boston: American Photographic Publishing Co., 1924, p. 259; Neblette, C. B. Photography, Its Principles and Practice, 4th ed. NY: Van Nostrand Co., Inc., 1946, p. 699.
2. Ware, Mike. New Cyanotype, Siderotype Workshop Notes. Buxton: self-published, 2009, p. 6. http://www.mikeware.co.uk/mikeware/downloads.html
3. Ware, Mike. Cyanomicon II, History, Science and Art of Cyanotype: photographic printing in Prussian blue. Buxton: self-published, 2016, p. 210. http://www.mikeware.co.uk/mikeware/downloads.html
Figure 7.9. Three Pebbles, classic and new cyanotype combined (SWC) © Sam Wang 2018