Cyanotype brush toning

AndrewBurns · Feb 6, 2025

Hi all, I've been getting good results with toning my classic cyanotypes in coffee (without bleaching) which tends to give me dark 'midnight' blue to purple tones, however some papers stain more than others and in some cases to a detrimental degree.

Normally I place the pre-soaked prints face-down in a large tray of coffee for about 30 minutes before rinsing, however I've heard that generally speaking all of the toning actually happens in the first 10 minutes. I'm wondering if instead I can just brush coat the coffee liquid onto the actual print area that I want to tone and then wash it off after a few minutes. This would allow me to use significantly less coffee and it would also reduce staining, at least of the edges of the paper, because those areas would never come in contact with the coffee at all.

Has anybody tried this? A quick google showed that at least one person had tried brush-toning with tannic acid and got good results, however I'm not sure if anybody has tried it with coffee and if that would have a different result.

koraks · Feb 7, 2025

It's a good idea! Note that on a wet print, the coffee may/will diffuse around the brushed area a little, but maybe this effect is sufficiently marginal so as not to pose a problem.
I've never tried this, nor do I recall having seen any examples of this with cyanotype in particular. Plenty of people have brushed toners on e.g. silver gelatin prints, which I've done myself on occasion, too, and yes, it does work. You generally need to brew a very strong toner because you'll only supply a tiny bit to the print that needs to do all the work, so you may have to brew a heck of a strong cup of coffee. This may offset any advantages w.r.t. staining.

AndrewBurns · Feb 7, 2025

Well brush toning with coffee definitely works. I did a small experiment by coating two prints twice (once while dry and once after washing), and two prints only once (dry only). No bleaching, but I think something in my tap water is already acting as a mild bleach (maybe the chlorine) as I notice my cyanotypes bleaching during washing anyway.

I'll upload some photos once the prints have dried a bit, but it seems to give similar results to bathing the prints except the paper outside of the image doesn't get stained and you can get away with using a LOT less coffee powder, which is a win. It's pretty easy to control where the toner goes when the paper is dry but harder if you try to coat wet paper. I wasn't really trying too hard to keep the toner constrained to just the image so there are a few spots around the edge where the paper is slightly stained from a bit of over-coating, but I don't mind a little controlled imperfection in this process.

AndrewBurns · Feb 7, 2025

These first two shots are two coatings of coffee, with a wash in between (starting from a dry print).

These two were a single coat, starting from dry.

I'm quite tempted to try mixing a very small amount of sodium carbonate into the coffee mixture to see if I can get a bit of a 'monobath' effect that simultaneously bleaches and tones. That might help to shift the shadows more, as currently the highlights are toned more strongly than the shadows which remain fairly blue.

fgorga · Feb 7, 2025

Nice!

In addition to trying sodium carbonate, consider trying calcium carbonate as well.

Sodium carbonate is much more soluble than calcium carbonate. A saturated solution of calcium carbonate has a pH of about 8. The pH of sodium carbonate solutions are in the range of 10-11. Thus the calcium solution will be a gentler bleach.

Patrick Robert James · Feb 7, 2025

Very nice Andrew. I like the smokey tones.

koraks · Feb 8, 2025

Great result @AndrewBurns ! Yes, the carbonate is a good idea. Try a pinch, or some calcium carbonate (whiting) as @fgorga suggests.

FotoD · Feb 8, 2025

Nice prints!

Keeping ammonia in a dropper bottle is quite convenient. You just put a couple of drops in the toner when you want a one-bath toner.

And don't forget to try brush bleaching as well.

fgorga · Feb 8, 2025

FotoD said:
Nice prints!

Keeping ammonia in a dropper bottle is quite convenient. You just put a couple of drops in the toner when you want a one-bath toner.

And don't forget to try brush bleaching as well.

Yes ammonia can be used to bleach cyanotypes. With the traditional bleach first then tone one generally gets a different hue in the final toned print.

See these posts for examples:

Tannic Acid Toning a Cyanotype

Popped together a video showing the toning of the print, Columns, being bleached and redeveloped in Tannic Acid. It's such a simple process...easier than shooting/editing videos! Both the untoned and toned print are in the Gallery. I hope you like it!

www.photrio.com

and

https://www.photrio.com/forum/threads/on-the-toning-of-cyanotypes.175185/

(Note: in this work I compared ammonia, sodium carbonate and sodium bicarbonate (baking soda). The pH of the bicarbonate solution used here is, most likely, similar to that of a calcium carbonate solution. However, I have not directly compared sodium bicarbonate and calcium carbonate.)

Also note that these comparisons use tannic acid as the toning agent rather than tea or coffee. I imagine that the results with tea/coffee will be similar but I have not compared them with tannic acid.

aconbere · Feb 9, 2025

AndrewBurns said:
These first two shots are two coatings of coffee, with a wash in between (starting from a dry print).

These two were a single coat, starting from dry.

I'm quite tempted to try mixing a very small amount of sodium carbonate into the coffee mixture to see if I can get a bit of a 'monobath' effect that simultaneously bleaches and tones. That might help to shift the shadows more, as currently the highlights are toned more strongly than the shadows which remain fairly blue.

I’ve got to say, that on top of appreciating the toning I love the presentation here. I’d love to know more about how you approach the coating? It looks like you use a brush but my brush coatings never look as neat and tidy.

AndrewBurns · Feb 9, 2025

aconbere said:
I’ve got to say, that on top of appreciating the toning I love the presentation here. I’d love to know more about how you approach the coating? It looks like you use a brush but my brush coatings never look as neat and tidy.

Cheers. Yes I use a brush, I forget the brand but it's quite wide with relatively stiff bristles, I'm pretty sure they're synthetic (much stiffer than the hake brush I used to paint the coffee on). Before I coat the paper I use a ruler and pencil to mark out the area that I want the coating to be within, recently I've been coating to about 8mm larger than the actual image area on each edge. This gives me some guidance for where to brush the sensitiser. I try to coat in slow long strokes from left to right, maybe 5 passes of the brush in one orientation before rotating the paper 180 degrees and doing the same thing again, going left to right. I probably rotate the paper two or three times total, working the sensitiser back and forth to try to get the coating as even as possible. I've gotten a feel for how damp the brush needs to be before I start so that the coating is uniform and dense enough without any leftover liquid at all on the paper.

I could obviously mask off the edges during exposure and that would leave only the image with crisp edges, but I like leaving the brushed marks around the edges so that it's clear the print is hand-made. I'm a bit of a perfectionist, so I see this as leaving the perfect amount of imperfection behind

aconbere · Feb 9, 2025

AndrewBurns said:
Cheers. Yes I use a brush, I forget the brand but it's quite wide with relatively stiff bristles, I'm pretty sure they're synthetic (much stiffer than the hake brush I used to paint the coffee on). Before I coat the paper I use a ruler and pencil to mark out the area that I want the coating to be within, recently I've been coating to about 8mm larger than the actual image area on each edge. This gives me some guidance for where to brush the sensitiser. I try to coat in slow long strokes from left to right, maybe 5 passes of the brush in one orientation before rotating the paper 180 degrees and doing the same thing again, going left to right. I probably rotate the paper two or three times total, working the sensitiser back and forth to try to get the coating as even as possible. I've gotten a feel for how damp the brush needs to be before I start so that the coating is uniform and dense enough without any leftover liquid at all on the paper.

I could obviously mask off the edges during exposure and that would leave only the image with crisp edges, but I like leaving the brushed marks around the edges so that it's clear the print is hand-made. I'm a bit of a perfectionist, so I see this as leaving the perfect amount of imperfection behind

It’s lovely, and the date, title, signature gives it a feeling like it’s in a folio or old science notebook.

I had mixed luck with the kind of free edge style and settled on sensitizing edge to edge and leaving a dark blue border.

But this has got me reconsidering. I’ll look for a wider stiffer brush.

AndrewBurns · Feb 12, 2025

Tried with the other brand of paper I use (Fluid HP watercolour) which stains significantly worse than the paper I used for my first prints. This is the paper I was most interested to try brush toning with because when dunking the paper I found the overall stain unacceptable. I think brush toning makes it much better, actually the highlight stain gives a nice split-tone warming effect which is probably quite suited to some photos. The brush coating of the Swiss Alps photo was a bit of a mess, I think my coffee solution was too concentrated or too hot because the print initially got quite mottled with weird speckly brown stains, but luckily the worst of that went away as it dried.

Cyanotype brush toning

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Tannic Acid Toning a Cyanotype

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Cyanotype brush toning

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