Just started to get back into Cyanotypes in the last month or so (September/October 2022), esp. after picking up a copy of Annette Golaz's new Cyanotype Toning book.
The book is full of great info, from the basics of making a cyanotype to extremely detailed notes on different papers and toning botanicals. It's greatly recommended; even if some of the experimentation ends up being a dead-end, the results I've already had from a couple of the toner colours makes it very much worthwhile. It even has an entire section on Tricolour prints - think Gum Bichromate prints but more ethereal - achieved by moving a print through a sequence of different toning and bleaching stages..
Here are a few notes/illustrations of what I've been up to working with Golaz's directions. Obviously I'm not going to give all her secrets away, but it's a good book that has transformed how I feel about making cyanotypes; the colours complement my argyrotypes, too, since the argyrotype colours are not particularly like those achievable with toned cyanotypes.
A few notes on toning that I've now learned:
• Paper choice. This is seemingly very important and worth experimenting with. Since I'm really not a fan of stained paper I've changed paper for cyanotype now to Hahnemühle Platinum Rag from Bergger Cot320. The additional bonus with this paper is that it comes in 11x15 as opposed to 11x14; these dimensions suit 3x2 prints better than the Bergger, and have allowed me to try printing cyanotypes from 35mm Leica film exposures via digital negatives printed on my Canon Pro 300 inkjet. The Hahnemühle paper is very very similar to the Bergger but perhaps just a slight bit less textured.
• Water and adjusting pH. What I hadn't at all appreciated before reading the Golaz book is how much water pH / chemistry affects colour and success when toning. I've now used a pretty rudimentary pH meter to test my home tap water, and work out how much bleach chemistry to add to distilled water for prints that need a bleach before toning. Changing the pH of the water for toning can dramatically change the colour of the print, and some colours are simply not achievable without some control over the water pH (whether neutral or slightly alkali). This is true for both my successful toning experiments recently. This compares very favourably, for instance, with my previous failed experiments, where toning either never occurred, or the paper was so badly stained that I gave up with Cyanotype completely.
My home tap water is pretty hard, and I find that a final wash of more than a few minutes in tap water tends to bleach/fade my raw cyanotypes, so I now simply wash quickly on each side with a shower head, then dry off with a squeegee. I hang to dry overnight, then flatten a set of prints under books for a few days.
My successful toner experiments:
1) Petrol Green: Achieved using Fenugreek seeds, steeped in boiling distilled water for 15mins before toning a print for an hour or so. Really quite an amazing colour, with a nice subtle split tone in the highlights shifting to yellow slightly. Does not noticeably stain the paper.
2) Purple: Achieved by first bleaching a print in a very weak alkali solution (distilled water and calcium carbonate) for 24hrs or so until pretty much all the blue has disappeared and the print seems basically yellow. Then toning for about an hour in a hot tea made from chopped Purple Smoke Bush leaves. Paper stain very mild if noticeable at all.
3) Blue-purple: Achieved by very quick toning in hot green tea. Any longer than even a minute and the paper stains and the nice purple colour achieved fades to tea-brown. If toned quickly, paper stain not very noticeable, but warm, slightly pink, highlights retained.
4) Subtle olive-yellow: Toning in a hot marjoram tea solution until desired colour achieved. You need a lot of dried marjoram for this! Paper stain is noticeable but not unpleasant.
5) Warm orange/yellow: Hot tea made with bay leaves, or with red rose petals. Paper stain quite noticeable.
Early pics below of successful prints and stages through the process.