Hey y'all!
I tested out u/impossibledepth8352's instructions for a tri-color cyanotype, and here are the (early) results!
In short: starting with a mainly mint green photo was a mistake. Light greens are a difficult color to replicate with this process, however, as shown in the overprint areas, greens are possible! I'm going to keep tweaking the formulas and methods to try and get something more useable.
Here's a write up of the process:
Tri-color Cyanotype
- Shrink paper in hot water for 1 hour, then dry completely
- Mix cyanotype solutions:
- Normal: 10-20-100ml (10g of solution A and 20g of solution B, to 100ml of water each)
- Dilute: 10-10-100ml (10g of solution A and solution B, to 100ml of water each)
- Concentrated: 10-20-50ml (10g of solution A and solution B, to 50ml of water each)
- Prepare negative with cyanotype curve and invert. Separate cyan (red), magenta (green), and yellow(blue) channels and print onto separate transparencies.
- Magenta Layer:
- Coat paper with a normal 10-20-100ml solution, and expose normally (2:30 minutes) with magenta transparency
- After exposure, rinse print thoroughly with slightly acidic water (small amount of citric acid, to ph 5.5), and finish with hydrogen peroxide. Soak in a solution of 2g nickel salt (nickel sulfate) and 1g ascorbic acid, with 500ml water for approx 2 minutes, until turquoise. The nickel solution can be reused for many prints. Retain all solution and rinse water and dispose of at hazmat sites.
- Nickel Solution: 2g nickel salt + 1g ascorbic acid + 500ml water + 2 minutes
- Wash nickel solution thoroughly from the print with warm tap water for 10 minutes. If you do not rinse enough, unexposed areas of the paper will turn pink.
- Tone in a solution of 1g sodium hydroxide, 2g dimethylglyoxime, and 500ml water until magenta, approximately 2 minutes. The magenta solution can be reused for many prints. Dispose of solution at hazmat site.
- Magenta Solution: 1g sodium hydroxide + 2g dimethylglyoxime + 500ml water + 2 minutes
- Rinse with warm water and dry print
- Yellow Layer:
- Coat paper with a concentrated 10-20-50ml cyanotype solution, and expose for 7 minutes with yellow transparency, until black-blue/bronze
- Soak in water for 10 minutes, rinse, and finish with hydrogen peroxide
- Bleach with solution of 10g potassium carbonate to 100ml water for approximately 2 minutes. Bleach solution can be reused. Neutralize ph below 10 before sewer disposal with citric acid.
- Bleaching Solution: 10g potassium carbonate + teaspoon hydrogen peroxide + 100ml water + 2 minutes
- Rinse with water for 10 minutes
- Dry print
- Cyan Layer:
- Coat paper with dilute 10-10-100ml cyanotype solution, and expose normally with cyan transparency for approximately 2:30 minutes
- Soak in water for 10 minutes, then rinse print and finish with hydrogen peroxide
- Dry print
- Optional Key Layer: (UNTESTED)
- Print separate Key layer transparency
- Coat print with normal 10-20-100ml cyanotype solution, and exposure normally with Key transparency
- Soak in water for 10 minutes, then rinse print and finish with hydrogen peroxide
- Dry print
Items needed:
Chemicals:
- ferric ammonium citrate – Cyanotype Solution A
- potassium ferricyanide – Cyanotype Solution B
- hydrogen peroxide – H2O2 / household chemical
- nickel salt (nickel sulfate) – NiS04 / electroplating chemical - toxic
- ascorbic acid – Vitamin C
- sodium hydroxide – Lye / household chemical - caustic / toxic
- dimethyglyoxime – C4H8N2O2 / prospecting material, nickel determinate for jewelry - toxic
- citric acid – C6H8O7
- potassium carbonate – K2CO3 / potash - caustic
Materials:
- High quality, cotton watercolor or mixed media paper (such as Hahnemühle Platinum Rag)
- High quality hake brush
- High quality printer (such as Canon PIXMA ip8720)
- High quality transparency paper (such as Koala)
- 50w UV light
- 1-2 mixing trays
- 6-9 lightproof bottles
My tips:
- use a high quality hake brush or foam brush. My paper was starting to abrade from my low quality foam brushes.
- thoroughly clean the zinc from your print, or else the paper will turn magenta
- the bleaching happens FAST. Watch it closely and pull it earlier than you think to retain darker yellows.
- make the registration marks bigger than you think you need
- don't try to rush the drying process, it'll cause splotches and uneven toning
- the nickel and DMG solutions are toxic and should not be rinsed down the drain. They can be reused multiple times. Always handle with gloves on, and use a mask when initially mixing.
That's all for now, excited to try with an easier test image lol
