Lexy Xiao finds a way to get around the expensive shipping costs of chemicals necessary for Chromoskedasic painting. She shares her process on how to prepare her own here.
WARNING: This is for experienced and advanced users only. Read the safety sheets before attempting to use chemicals and use the correct safety equipment. Hazardous chemicals are used.
A little history and science on chromoskedasic painting
In the 1990s, Dominic Man-Kit Lam coined the term ‘chromoskedasic’, which means colour by light scattering, for his discovery of making colourful paintings on B&W photographic paper without any pigments. He pointed out that the colours of painting rely on subtractive colour. For example, blue pigments reflect blue light while absorbing most other wavelengths of light. However, in chromoskedasic painting, the silver particles in photo paper produce colours through the process of Mie scattering. The theory of Mie scattering describes the wavelength of light scattered by a medium, which consists of spheres of similar size and electrical characteristics, depending on the size of the spheres. Chromoskedasic painting applied chemicals to form silver particles in different shapes and sizes, which can scatter different colour light wavelengths to yield colours. These colours are often observed by photographers when the photographic chemical solutions deteriorate (Lam, 1991, pp.80-85). Then William L. Jolly combined chromoskedasic painting with Sabatier; he detailed the required chemicals are the activator (potassium hydroxide solution) and stabilizer (acetate buffered thiocyanate solution); he also specified the process in his book Solarization Demystified (1997). After Jolly, Alan Bean (2009) and Christina Anderson (2009) also explored the technique and processes.
This article is for carrying out the process without ready-made products. The products are hard to get outside the US. I did research and analysis on the chemical ingredients of the products to be able to make a recipe for my activators and stabilizers. The activators and stabilizers are made from scratch with chemicals that are possible for me to get. I conducted experiments on chromoskedasic painting based on the processes from Anderson (2009) and Crawford (2018), to test my recipes.
“I share my two recipes, my experiment processes and my discovery, so that others who cannot get hold of ready made products can try the process, and for the further development of the process; one of the recipes does not give off an ammonia smell ☺.”
Just to clarify:
- potassium hydroxide = KOH
- acetic acid = CH3COOH
- Ilford Rapid fix (directly from the bottle) = fix
- potassium thiocyanate = KSCN
VERY IMPORTANT: Label everything CLEARLY when doing the preparation; read MSDS of the chemicals before the experiment; wear safety equipment for ALL the experiments.
What you need for Chromoskedasic painting
- Ordinary black and white darkroom chemistry; I applied Ilford developer and rapid fix
- Gelatin silver paper; I tested Ilford FB warmtone, art, RC pearl, RC warmtone and cooltone pearl, and some expired and fogged FB and RC papers
- KOH flake; I applied a 90% concentration
- White vinegar or acetic acid; I applied a 35% concentration, check there are no other additional ingredients if using a white vinegar
- KSCN flake; I applied a 98% concentration
- Trays and tongs
- Measuring cylinders
- A scale
- Masking tape and pen for labelling the chemicals
- Safety equipment is absolutely necessary: fume mask, gloves and goggles
Chromoskedasic painting Recipe 1
Acetic acid diluted fix as the stabilizer, with an ammonia smell when mixed with the activator or developer; wear a fume mask if you conduct this indoors.
- Activator: 10% KOH solution; add 50 g KOH flake to cold water to make a 500 mL solution in total; be careful as the dissolving process will give off a lot of heat.
- Stabilizer: (5% CH3COOH + 20% fix) solution; add 250 mL fix to 179 mL cold water, and then add 71 mL of the acetic acid to the mixture to make a 500 mL solution in total.
If you have other dilutions of the white vinegar or acetic acid, here is a formula to reach 5% CH3COOH:
Aimed dilution x desired amount of stabilizer in ml÷the dilution of your product.
For example: 5% x 500 mL÷35%≈71 mL
- Developer: normal diluted developer.
- Prepare 100 mL each (activator, stabilizer and developer) in separate, smaller containers for drawing, three brushes for each (it is better not to mix the brushes and keep the solution clear), and a large tray or tank of water for rinsing; label everything clearly.
- Make a regular print under the enlarger and develop it; no need to stop and fix but rinse it in water for 0.5-1 minute and then drain it. Or apply a plain and unprocessed photo paper. It is better to have some test strips. Do everything with the safe light on.
- Make sure your other darkroom materials are safe and turn on the light; then the paper will change colour quite quickly due to the exposure. You can immediately draw the three solutions in different orders; the messier you draw on the print, the more colours there will be. Basically, the developer darkens the print; the activator boosts it; the stabilizer slows it down.
- The colours will grow for a while; if it reaches the visual effect you want, immediately rinse it in water; for FB paper rinse 1-2 hours.
- I did not fix the print for this recipe, because the rapid fix would wash away the colours, and I want my prints to grow, but you could try a salt bath or hypo fix (sodium thiosulfate).
- If the print is not fixed, dry it in the dark.
Conclusion and suggestion
- The experiments for this recipe were on Ilford FB warmtone glossy paper.
- The parts where the three solutions meet can bring intriguing colours; using more activator tends to create more red, brown, and warm colours; more stabilizer tends to give green, blue, cold colours. According to Jolly, and also mentioned by Anderson and Crawford (1997, 2009, 2018), higher PH levels of developers tend to give warm tones and lower tend to give cool tones. It matches that KOH is an alkali which could increase the PH; acetic acid diluted fix tends to decrease the PH.
- The brush strokes can show up on the prints; any other tools you draw with would leave patterns too; even water stains would leave traces, because the print is still sensitive to light when you draw in the light.
- A developer contaminated by the activator and stabilizer could cause random silver mirroring when it is for developing the latent image on this paper, but would disappear if being fixed by rapid fix.
- You could have the fourth solution to draw with, which is the 1:1 mixture of activator and stabilizer at first; I would keep the used mixture for reuse (the waste should be collected anyway), because the older the mixture is, the better the effect will be.
- You could combine the drawing method from the second recipe.
- You could combine the drawing with Sabatier: just skip the rinse in the second step.
- If the print is too dark, you could try to bleach it afterwards, but it would make the silver mirroring disappear on this paper.
Chromoskedasic painting Recipe 2
KSCN solutions as the stabilizer and the fix bath in different dilutions, without the ammonia smell☺. You should wear safety equipment anyway.
- Activator stock: 10% KOH solution; add 30g KOH flake to cold water to make 300 ml solution in total, be careful as the dissolving process can give off a lot of heat.
- Stabilizer stock: 20% KSCN solution; add 60g KSCN flake to cold water to make 300 mL solution in total.
EXTREMELY IMPORTANT: Keep the KSCN away from any acids; if contact with acids liberates very toxic gas!
- KSCN fix bath: 1:120 KSCN solution;
Method 1: get 12.5 mL stabilizer stock in a measuring cylinder and then add cold water to make a 300 mL solution in total (refer to the formula in recipe 1 to reach 1:120 for a desired amount of the solution; e.g. 1/120 x 300 mL÷20% = 12.5 mL).
Method 2: add 4.2g KSCN flakes to cold water to make a 500 mL solution in total.
*The KSCN fix bath is modified from Jolly’s idea of the NaSCN (sodium thiocyanate) fix bath (1997), which was also mentioned by Anderson (2009); it is based on the chemical similarity among NH4SCN (the one that causes ammonia smell ☹), NaSCN and KSCN.”
- Activator for drawing: 2% KOH solution; get 20 mL activator stock in a small measuring cylinder and then add cold water to make a 100 mL solution in total (different desired amounts refer to the formula too).
- Stabilizer for drawing: 4% KSCN solution; get 20 mL stabilizer stock in a small measuring cylinder and then add cold water to make a 100 mL solution in total (different desired amounts refer to the formula too).
- Mixture for drawing (Activator+Stabilizer): 1:1 activator stock and stabilizer stock; get 50 mL activator stock in a small measuring cylinder and then add 50 mL stabilizer stock in the same cylinder, to get a 100 mL mixture in total.
- Developer: normal diluted developer.
- Prepare 4 individual brushes for the 4 solutions for drawing (Activator, Stabilizer, Activator+Stabilizer, Developer) and a large tray or tank of water for rinsing.
- Make a regular print under the enlarger and develop it; no need to stop and fix but rinse it in water for 0.5-1 minute and then drain it. Or apply to plain and unprocessed photo paper. It is better to have some test strips. Everything is in the safe light.
- You could plan where you would like to draw with Activator, Stabilizer and Activator+Stabilizer, and then draw them on the print in the safe light.
- Then turn on the light and immediately draw Developer on the whole print, then the colour will change and silver mirroring could happen; if colours change too fast, draw more Stabilizer, too slow draw more Activator or Developer; but it needs Developer to make the massive colour change happen.
- The colours will grow during the drawing, but it will reach a point where there is no obvious and visible change; if the print reaches the visual effect you want, just immediately rinse it in water for a few minutes.
- After the rinse, put the print in the KSCN fix bath for 5 mins with agitation for a while.
- Rinse the print; RC paper for at least 5 mins.
- Dry it on the shelf; the room light is OK. I did not use any dryer, not sure if it would influence the visual effect.
Conclusion and suggestion
- The experiments for this recipe were on Ilford art, RC pearl, RC warmtone and cooltone pearl, and some expired and fogged FB and RC paper. I found the RC paper showed the metallic sheen easier than the FB paper. The silver mirroring effect (the metallic sheen) on the RC pearl is the strongest, then the cooltone, the warmtone. For warmtone there is a tarnished metallic effect. However, I enlarged different images on different paper; the image you choose could influence the result, more or less.
- More Activator+Stabilizer tended to give golden yellow and orange; more Stabilizer tended to give greenish and bluish; more Activator tended to be warmer brown reddish colours or to darken the drawn areas; more Developer would darken the drawn areas; the colours emerged when the solutions met on the print in the light.
- I kept the used KSCN fix and the Activator+Stabilizer mixture in the same waste collection container for reuse of the mixture for drawing; the old mixture has a better effect.
- There is no obvious visual change on the prints if viewed in room light or natural light after the KSCN fix; I installed them on the wall for about a month.
- For both recipes, putting the print into a 1:1 Activator and Stabilizer mixing tray did not work well for me. For the first recipe, the print tended to be a fogged brownish and greyish colour; for the second (only the warmtone paper), the print tended to be golden yellow and orange.
References for Chromoskedasic painting
- Anderson, C. (2009). Quick and Easy Chromoskedasic Sabatier. Available at:
- Bean, A. (2009). Silverized Chromoskedasic prints. Available at:
- Crawford, M. (2018). Chromoskedasic Sabattier: a step-by-step guide. Available at:
- Jolly, William L. (1997). Solarization Demystified. Historical, Artistic and Technical Aspects of the Sabatier Effect
Department of Chemistry, University of California, Berkeley, California 94720, Copyright 1997 by William L. Jolly.
Available at: http://web.archive.org/web/20030112112441/http://www.cchem.berkeley.edu/wljeme/Chapt6.html
- Lam, D. and Rossiter, B. (1991). ‘Chromoskedasic Painting’, Scientific American, (Nov/Vol. 265, No. 5), pp. 80-85