Cyanotype is a easily accessible process with one limitation. It’s blue. Unless you know how to create multi-coloured cyanotypes. Here is how.

Writer and photography / Jo Bind with tricolour section by Sehera Nawaz

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It was literally out of the blue when I first saw a post by Annette Golaz on the cyanotype Facebook group in early 2021 which showed a full-colour print that she claimed was done with cyanotype chemistry. I was sceptical since I’d never seen anything like it. Bright, clean colours – reds, yellows and blues. I didn’t think it was possible.
Fast forward a few months, I sat at Singapore Airport in the transit lounge when I saw another post by Annette, announcing a workshop on tricolour cyanotype printing in Berlin a few weeks later. As luck had it, I happened to be in the area at the time and had the great fortune of participating in the workshop. And it fully changed my perspective on the artistic possibilities of cyanotype printing.

In most cases, when art is concerned, limitations further artistic development. Cyanotype isn’t any different in that regard. Limiting yourself to a purely blue colour palette poses great challenges, but also lets us develop quickly in our artistic expression. However, blue isn’t a suitable colour for every subject – as the initial reactions of my friends suggested when presented with (well-executed, but ultimately rather blue) portraits of themselves. Or, as Peter Henry Emerson famously wrote in the late 19th century: “No one but a vandal would print a landscape in red or in cyanotype.” I disagree with Emerson’s all-encompassing rejection of cyanotype for landscapes (seascapes and icy mountaintops print rather well in the process), but I do agree that for most landscapes, it’s far from the ideal colour.

“To make cyanotype printing a more universal process (i.e., printing all sorts of subject matter), I started experimenting with toning the prints early on in my practice. The holy grail for me initially was to create a perfectly neutral black and white print – which proved to be a difficult goal to achieve without excessive paper staining. I had some reasonably successful prints, but it was never predictable and resulted with a high degree of regularity in failure.”

After creating a successful tricolour cyanotype print with Annette’s help at the workshop (all participants created beautiful, multi-coloured prints, regardless of their previous experience), I set out to try printing this way by myself. By then, Annette had published her seminal book Cyanotype Toning – Using botanicals to tone blueprints naturally and it contains all the information you need to print cyanotypes in colour. The biggest hurdle in the process, I found, was creating the magenta layer, since it requires a botanical that’s difficult for me to source in an acceptable quality in New Zealand, where I live. After many failed attempts, I was ready to give up until I would manage to source good dyeing materials. But then it hit me: what if I could create a print using only the ‘easy layers’ – yellow and cyan – and not bother with the dreaded magenta layer at all?

In the next section, I will introduce the process for duotone cyanotype prints, using yellow and blue layers. In the section after that, Sehera expands on this process and introduces the extra steps required to make full-colour cyanotype prints.

Duotone Cyanotype Printing

The subject matter(s)
Possibly the most important step with this method is finding the right image to print in this process. Since we are printing a limited colour palette without any reddish tones, we have two choices: finding images that have little to no red or printing a deliberate ‘false colour’ image. I haven’t explored the false colour realm enough myself, so this section will focus on creating realistic looking images with just a palette of blues and yellows – by carefully choosing appropriate images. However, the same steps can be followed to create false colour images. The image above, “Optimism” (from my series Minimalism), is a good example for an image that perfectly lends itself to this process. The original digital image contained very little magenta (apart from some rust under the stairs), so a print without magenta would look perfectly natural. Once you start looking for suitable images, you’ll be surprised what you might find. And, if you incorporate this process into your own work, it might even influence you in your choice of subjects to photograph.

The multi-coloured cyanotype print process, step-by-step

1. Image preparation (editing, saturation adjustments)
2. Creating colour separations
3. Apply colour-specific calibration curves
4. Invert images and print negatives
5. Coat paper, expose Yellow negative (3x exposure time)
6. Develop and wash print
7. Bleach Print
8. Rinse and dry
9. Re-coat paper, expose Cyan negative (regular exposure time)
10. Develop print
11. Dry print

Step 1. Image Preparation

This part is based on the results of Annette’s extensive research into the process to yield colours as close to real life as possible.
As a general rule of thumb, multi-colour cyanotypes display more muted, as opposed to vibrant, colours. This is probably partly due to the matte nature of the watercolour paper, but also the bleaching of the print in the process. To counteract this behaviour to a certain degree, Annette has found that boosting the saturation of the digital image (after all the editing has been done) by 30-50% results in better prints. The exact amount depends on the nature of the colours in the image. If it contains highly saturated colours already, less of a saturation boost is required. Don’t panic if the image looks a bit garish after the application of the extra saturation. This is perfectly normal and will look very different in the resulting print.

Step 2. Creating colour separations

As with all multi-colour processes, the original image needs to be split into individual negatives for each of the colours (in our case, we’re only using the yellow and cyan layers, but the process is the same). To do this in Photoshop, we need to flatten the image first (thereby applying any correction layers, like the saturation layer of step 1 above). Then we save a copy of this image (since you won’t be able to undo the next step). Next, go to Channels->Split Channels. This will open three new windows, each with a different grayscale image. The name of the window will indicate which channel it represents. _Red is used for the Cyan layer, _Blue is used for the Yellow layer (cyan is the complementary colour of red and yellow the complement of blue). In our case of cyan-yellow duotone prints, we’re just discarding the _Green (magenta negative) layer.

Step 3. Apply colour-specific calibration curves

As with the regular cyanotype process, a calibration curve has to be applied to the image to correct for the non-linear translation of the tonal values in the negative to the printed tones. Generating calibration curves is beyond the scope of this article, but there are numerous sources of information (books, videos, websites) available on how to do this. See the Tips & Tricks section in the end for some links. The important thing to note in reference to the multi-colour cyanotype process is that each colour requires its own curve!

Step 4. Invert images and print negatives

Since we print with negatives for cyanotype, we need to invert the image (with its correction curve applied!). We also need to flip the image horizontally to keep the correct orientation. Then print the yellow and cyan negatives on your transparency of choice. For many images, it is very difficult to identify which negative is the yellow and which is the cyan layer. Therefore, I like to include a “Y” or “C” somewhere on the transparency to make sure I know which is which.

Step 5. Coat paper, expose Yellow negative (3x exposure time)

Coat your paper with the cyanotype solution and let it dry for 15-30 mins before exposure. Then expose the Yellow negative under your UV source for 3x your normal cyanotype exposure time. Since the yellow layer is created by bleaching a regular cyanotype print (and the bleaching removes a lot of detail), it requires a lot more UV exposure to retain information in the highlights. The resulting exposure will look VERY overexposed (lots of dark blue, highlights stained blue and potentially lots of bronzing depending on the overall tonality of the image). Don’t worry, that’s normal.

Step 6. Develop and wash print

Develop your print as you normally would. I’d recommend you to develop in mildly acidified water. I personally use white vinegar for this, but citric acid will work similarly. You’re aiming for a slightly acidic wash (pH around 5-6 or so), not a highly acidic solution. After the initial development, wash the print in regular tap water until all traces of yellow are removed.
If you normally don’t use hydrogen peroxide and let the darkening of colour occur naturally during the drying, you should use it for this process if you want to bleach right after development. Since the bleaching step will take time, I’d recommend to do it right away after a short bath in hydrogen peroxide. Alternatively, you can let the print dry and darken for a day and then proceed with the bleaching step.

Step 7. Bleach Print

This step removes all blue from the image and what you’re left with is a (much lighter) image in yellow.

It’s important to fully bleach the image until there are no traces of blue left. To preserve as much of the highlights in the yellow layer as possible (the yellow layer is a case of “what you see is what you get”), the bleaching solution should not be too concentrated. It’s not useful to specify amounts of bleaching agent per litre of water, since the local water supply will have differing acidity/alkalinity. Measuring pH is a better way to achieve consistent results. A target pH of between 10-11 is desirable. If the print starts to vanish as soon as you immerse it in the bleach, your concentration is too strong and much of your highlights will be gone by the end. If the bleach solution is used at room temperature, bleaching will usually take 6-10 hours (you can do this overnight). However, if the solution is heated to about 50 degrees Celsius, full bleaching is reached in about 60 minutes.
Different agents can be used to bleach the print, each resulting in a slightly different shade of yellow. Common agents are sodium carbonate (washing soda) and household ammonia. I prefer bleaching in sodium carbonate because of its low toxicity as compared to ammonia. And the smell of ammonia can be overpowering.

Step 8. Rinse and dry

Once the print is fully bleached, it needs to be rinsed very carefully. Since we’ve just immersed the print in a bleaching solution (which would react with the next layer of cyanotype solution if traces remain), the washing process needs to be done very thoroughly. I generally soak in tap water (non-chlorinated) for about 10-15 minutes with at least 2 changes of water. After the rinse, the print needs to be fully dried.

Step 9. Re-coat paper, expose Cyan negative (regular exposure time)

Proceed with a coating over the yellow print with cyanotype solution and let the paper dry (as in step 5). This time, you’ll expose the cyan negative. Make sure that you get the negative aligned properly over the yellow layer or you’ll have a misregistration, resulting in a blurred image or double edges in yellow and blue (which can be a feature if desired). See Tips and Tricks at the end of this article for further information on paper and registration. The negative is then exposed according to your regular printing time for cyanotype.

Step 10. Develop print

Develop the print in acidified water as described in step 6 above. This time, the use of hydrogen peroxide is completely voluntary, since the blue tones will develop to their full richness by themselves over the drying period. However, for those impatient printers, who want to judge the print in all its glory right away (me!), a quick immersion in water with a few drops hydrogen peroxide will give you instant gratification (hopefully, if the print turned out well).

Step 11. Dry print

Colours will change a little over the drying period, but if you’ve used hydrogen peroxide in the last step, your print will look pretty close to the final image even when wet. If you’ve skipped the hydrogen peroxide, the print will develop substantially over the drying time.

This is the final print resulting from the steps described above:

Beyond duotone

Besides duotone printing – or printing images that only contain a limited colour palette – it is possible to print full-colour images with cyanotype. The process of tricolour cyanotype printing is described in the section below. This part is written by Sehera Nawaz, a Berlin-based artist, who has been printing multi-coloured cyanotypes for a number of years and has extensive knowledge about the process.

I must confess that I have personally had only limited success with printing satisfactory tricolour cyanotypes. I find adding the magenta layer complicates the process considerably.

A number of botanicals that cause cyanotypes to turn reddish are described in Annette’s book, but she’s settled on using madder root for her magenta layer. I’ve also experimented with boiled avocado skins, which (when boiled in alkaline water) also turn a pinkish colour. However, the paper stain with avocado skins is very strong (i.e. the paper turns a dark pink instead of staying white). Sehera uses a different botanical altogether in her process as described in the section below.

All red-dyeing substances have this paper-staining effect to some extent, but madder root seems to give a very good overall balance. One of the reasons I don’t seem to be able to replicate the results from Annette’s workshop here in New Zealand is that I don’t have many sources of madder root and what’s available to me simply doesn’t give the results I’m looking for. It does work, but it’s a different tonality from what I personally seek. The beautiful image by Gela* above was printed with my local madder root and shows that it can indeed work wonderfully for images with the right natural palette. It’s more of a subdued magenta, tending to brown, which works well with the sandstone in the image. Personally, I am often looking for a bolder statement and I can’t get the saturated tones that I want.

As with duotone cyanotypes, the choice of subject matter is an integral part of the printing process. While it is theoretically possible to print any colour scheme possible by mixing magenta, yellow and cyan layers, the resulting images from this process are generally more subdued than bold. The process lends itself to soft, dreamy or muted images as they can be printed more easily than saturated colours.

Tricolour Cyanotype Printing by Sehera Nawaz

The first tricolour print I did was in 2017, but it didn’t turn out great and I was a bit discouraged. However, I found using red and blue already gave me some pleasing results, so I stuck to that (basically duotone as described above) with red instead of yellow. It was not until Annette came along and showed us all what is possible with tricolour, that I started the process again and I will be forever grateful for her encouragement and the knowledge that she brought to this process!

The tricolour printing process is a bit tricky and there are still so many things open for research and discussion; but I will present my version of it here in the hope that many more people will adapt it and find solutions to the tricky nature of this printing process.

To print a tricolour cyanotype, we will use all three negatives created from the RGB components – these are the negatives for cyan, magenta and yellow respectively. In the cyanotype world we cannot print cyan, and the reddish tones we can create with toning do not quite resemble magenta. Yellow, as we saw in the previous section, is doable through bleaching.

There are two options to overcome these limitations: The one I prefer is to just be happy about the colour shift and see it as part of the technique. The other option is to mix the negatives for magenta and yellow to get a negative for red and to mix the negatives for magenta and cyan to get a negative for blue. To do that, you load the two negatives as layers and set the opacity of the top layer 50%.

Regardless of which method we chose, we still need a way to create the red/magenta layer of the print. Cyanotypes react with any substance that has tannins. In Anette’s book, she tested many different tannin-rich plants, that all result in quite different colours. To make things even more difficult, most plants have a diverse set of tannins that might not all give you the wanted results. Another parameter is the water quality, as toning results differ depending on pH and hardness.
When toning, you also have to deal with toning/staining of the paper. We found, that this is not that much of a problem in this process, as we wash the paper several times after toning and also the exposure to UV light bleaches the paper stain. The colour that is created from the interaction of the Prussian blue with tannin is a stable chemical reaction, although the colour can change a bit in the first few weeks.

I believe it is a new search for every printer to find the red that is best suited for them, as supply of available materials differs and the colour you get is also dependent on your local water supply. Here in Berlin, we have quite hard water and that results in a really strong red from one specific Celyon black tea. But Annette found a different and stronger red by toning with madder root. In general, Annette’s book on toning is a great start on your search for your red toning agent.

To use madder root you should soak it a day before and discard the water before making an infusion. For any tannin substance, you prepare a strong infusion and let it cool down to about 20-30°C before toning your cyanotype in it.

The steps for the tricolour cyanotype process are the following

Just 15 steps, easy!

1. Image preparation (editing, saturation adjustments)
2. Creating colour separations
3. Apply colour-specific calibration curves
4. Invert images and print negatives
5. Coat paper, expose your red/magenta layer
6. Wash and use hydrogen peroxide to get the fully developed Prussian blue
7. Tone your cyanotype in your favourite red
8. Dry and recoat
9. Expose your cyanotype with the yellow negative
10. Wash + hydrogen peroxide
11. Bleach with washing soda as described above
12. Wash really thoroughly
13. Dry and recoat
14. Expose your blue layer
15. Wash + hydrogen peroxide

DONE!

Steps 1-4 are described in the previous section on duotone cyanotype printing.

• Image preparation (editing, saturation adjustments)
• Creating colour separations
• Apply colour-specific calibration curves
• Invert images and print negatives

Step 5. Coat paper, expose your red/magenta layer

Coat your paper with cyanotype solution and let it dry. Expose the magenta/red negative to UV light for 1.2 to 2 times longer than your regular cyanotype exposure.

Step 6. Wash and use hydrogen peroxide to get the fully developed Prussian blue

See step 6 in the duotone section for details.

Step 7. Tone your cyanotype in your favourite red

Slide the print into the toning bath and agitate every now and then to make sure no bubbles are trapped on the surface of the print. The toning time is different depending on your favourite red. A good starting point is about 10 min in lukewarm toning solution. The warmer the solution, the shorter your toning times, but if it is too warm the paper might suffer and paper staining might increase. Annette proposes about 2-3 hours for her madder root solution (see the Tips & Tricks section at the end for more information on using madder root). She also proposes to bleach the print before toning. This is something to keep in mind on your search for red: the red changes depending on bleaching before toning or bleaching after toning. If you bleach after toning, then you can bleach the print just once for both the red and yellow layers (after the yellow negative has been exposed). When using this method, you can’t see the final red toned version, as you will print the yellow layer before toning. So don’t be discouraged if it is still quite blue and not really red.

Steps 8-11 should be clear (see notes specific to the yellow layer in the section on duotone printing).

• Dry and recoat
• Expose your cyanotype with the yellow negative
• Wash + hydrogen peroxide
• Bleach with washing soda as described above

Step 12. Wash really thoroughly

The wash after bleaching is crucial, as any leftover washing soda will bleach your blue layer after exposure. So don’t only rinse it but soak it in water for a few minutes and change the water every now and then.

Steps 13-15 are normal procedure.

• Dry and recoat
• Expose your blue layer
• Wash + hydrogen peroxide

A few things to keep in mind

The exposure time for all three layers differs from a single layer cyanotype. I found that even the blue layer has to be a bit overexposed to get a good result. As described in the duotone section, the yellow layer requires about 3 times normal exposure and the red is about 1.2 to 2 times normal exposure. The blue layer is just about 1.2 times normal exposure.
The time for toning also depends on your toner and preference. I use about 10 min in freshly prepared tea. When you reuse your tea be sure to add a fresh batch every now and then, as the tannins get used and new ones are needed.

Don’t be scared if, after the bleaching, your print looks like it lost all depth. At that point, you should have a duotone cyanotype with red and yellow, which are both weak colours. It looks kind of orange and not really usable. The blue layer adds most of the contrast and pulls the image together.

Don’t judge your print until it is dry. The blue usually looks too strong at the beginning. When it is dry and it is still too strong, you can try bleaching it a little. Either by just washing with (hard) water or by adding just a tiny bit of washing soda. Be super careful; I destroyed many prints that way! But the good thing: If your last layer is not strong enough, you can always re-coat and re-expose the blue layer.

We are all still looking for the elusive green in prints using the techniques described above, but I think with Jo starting his duotone journey with yellow and blue, I am more confident than ever, that green is possible! Jo showed me that calibration is key here. The more people try this process the more we will find possibilities for new colours to appear. That makes me super happy! Please share your results, if you ever try it!

Tips & Tricks for tri-colour cyanotypes

While it is certainly possible to print images in duotone or tricolour cyanotype that have a completely natural looking colour palette, it very much depends on the subject. When starting out with these processes, don’t expect a inkjet look-alike print or even something like a gum print. These cyanotypes will have a softer, more gentle look for the most part. Be open to what comes naturally, rather than trying to force it a certain way. This attitude will lead to more satisfying results sooner.

If you’re toning with madder, try this process to start with: the day before toning, soak roughly 25 g of madder root in 500 mL of water. This softens the roots a bit and removes some of the intense, staining colouring. The next day, discard the soaking water and finely cut the soaked roots. Ideally, you’d use a food processor, but you can cut them by hand. Just try to chop them as finely as you can. Put them into a stainless steel saucepan and add 0.5 g of calcium carbonate (this alkalizes the solution slightly, giving redder rather than yellow colours). Add 1000 mL of water at a temperature of about 60-65 degrees C (not hotter, or the colours will change). Stir and cover the pot with a lid. Let the roots infuse for about 15 minutes, then strain the liquid into the tray that you’ll use for toning. Try to cover the tray to keep the solution warm as long as possible—this speeds up the toning. This hot toning solution is used in the toning step of the process. Annette recommends toning for 2-3 hours.

A word on calibration and digital negatives: try to calibrate/linearize each colour as best as you can. This is difficult and labour intensive, no doubt about it. Especially for the yellow layer, which has a much reduced range of luminance values. But the better your calibration is, the more YOU are in charge of what the final print will look like and the more realistic your colours will come out. If you’re using Epson printers, I’d highly recommend Richard Boutwell’s Quadtone Profiler – Quick Curve DN software (https://www.bwmastery.com/quadtoneprofiler-digital-negatives). It will make linearization much easier. For a very thorough run down on the creation and linearization of digital negatives, I highly recommend Bill Schwab’s series of Youtube videos on the subject (https://www.youtube.com/watch?v=TMmG1wzVxEM). It will cover everything you need to know.

A final word on alignment of the different layers. This requires some practice and preparation and is best done on a light table. I usually use the natural “frame” of the image (i.e., the area that is covered by the negative) as a reference for alignment. If the printed layers aren’t perfectly aligned with one another, the image will appear blurry (if shifted only very slightly) or sharp edges will appear twice. This can be used as an artistic effect as shown in the image “Hanoi Scooter” below, but is generally a flaw rather than a feature.

When printing multi-coloured cyanotypes, the paper is wetted for extended periods of time during development and rinsing. This causes the paper to shrink (just like a new t-shirt in the wash), so by the time the second layer is printed, the negative does not fit the existing print anymore. To avoid this (or at least minimize the effect), it’s best to pre-shrink the paper in hot water. I do this with about 20 sheets at a time. I fill a tub with hot water from the tap and immerse the sheets one after another in the hot water. I then shuffle the stack from time to time to give each sheet equal exposure to the hot water. I keep them in the tub for 30-60 minutes, then hang them up to dry (a clothes rack is perfect for this). When they’re dry you can store them and they’re ready to print.

Further inspiration for multi-coloured cyanotypes

If you want some more inspiration, there are currently a few people working with multicoloured cyanotypes. Besides Jo’s (www.maverickaesthetics.net), and Sehera’s (www.solarlamp.de) websites, there is of course by Annette Golaz (www.agolaz.ch), the author of The Definite Guide of Toning Cyanotypes.

Sehera Nawaz is an analog and alternative photography artist, specialized in Cyanotypes. Having in-depth knowledge about behavior of light through studying and publishing in the field of film rendering/computer science, she uses her knowledge since 2015 to research and explore old photographic printing techniques. Studio and workshops at MAHLOWER EINS (Facebook link), Berlin Neukölln. https://solarlamp.de, Instagram: @dead_uncle_photography

Jo Bind has been using cameras since being given his first camera at the age of 8. When digital cameras became available, he quickly transitioned to the new medium and, after nearly 20 years, has started using film again in 2020, this time in medium and large format. In 2020, he also started to explore traditional photographic printing techniques, with the main focus being on cyanotype and argyrotype, but also dabbling in gum bichromate, gumoil and platinum-palladium printing. Instagram: @maverick_aesthetics_photo