I've got the blues - Cyanotype pain

cirwin2010 said:

It could be? If I'm looking at the correct paper it appears to be a lot more expensive, more difficult to source, and doesn't come in smaller sizes. For those reasons I haven't tried it. I'm also hesitant to try different papers for cyanotype right now give all my difficultly with getting the sensitizer to absorb evenly.

Eventually I'll try some other cotton papers to see if I can find one that works as well. I do agree cotton is a much nicer material than cellulose, especially when holding it or

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fgorga said:

Superior in what way?

Canson XL watercolor is an inexpensive paper that works well with traditional cyanotype, an inexpensive alt process. It is a great place to start.

There are many papers that work with cyanotype especially if you are willing to treat the paper with acid to remove the carbonate buffer present in many papers. Maybe it is a bit counter intuitive, but many inexpensive papers work well for cyanotype right out of the package probably because they do not have any (or only small amounts) of carbonate buffer in them. Carbonate is added to 'fancy' papers so that they meet one of the standards for archival-ness which less expensive papers may ignore.

A good resource for alt process papers is "The Massive Paper Chart" (see: https://www.alternativephotography.com/massive-paper-chart/). If you do a lot of alt process work the paid version is well worth the money but there is also a free version with just the basics (scroll down on the cited page).

Lastly, with regard to carbonate buffers and pre-treatment of papers with acid, I find that if I 'develop' my cyanotypes with a first wash of 15% vinegar instead of plain water, I can use papers that would otherwise require acid pre-treatment straight from the package.

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Thanks for your reply,
I have a history of using 100% rag papers with pt/pd, so I'm cautious of cellulose paper. That's why I questioned the Canson Edition paper against the Canson XL watercolor which is cellulose. I'm ordering some Canson XL to try it.
I have the "Massive Paper Chart". Maybe I missed some information there.. It's hard to know how much calcium carbonate is in each paper with regards with how to treat it.
Also, doesn't that 15% vinegar wash bleach your fine highlight detail?

jda said:

Thanks for your reply,
I have a history of using 100% rag papers with pt/pd, so I'm cautious of cellulose paper. That's why I questioned the Canson Edition paper against the Canson XL watercolor which is cellulose. I'm ordering some Canson XL to try it.
I have the "Massive Paper Chart". Maybe I missed some information there.. It's hard to know how much calcium carbonate is in each paper with regards with how to treat it.
Also, doesn't that 15% vinegar wash bleach your fine highlight detail?

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I can't speak to fgorgas vinegar wash, but I acidify the paper in 10% sulfamic acid until it stops fizzing (about 25-30 min) then give it a thorough wash.

The surface layer stops bubbling really quick in the sulfamic acid, but it takes much longer to neutralize the center of the paper fibers. Small jets of bubbles will appear at the paper edges after a while.

fgorga said:

with regard to carbonate buffers and pre-treatment of papers with acid, I find that if I 'develop' my cyanotypes with a first wash of 15% vinegar instead of plain water, I can use papers that would otherwise require acid pre-treatment straight from the package.

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I believe this is in the context of Classic Cyanotype and the same vinegar developer wouldn't work for New Cyanotype without pre-treatment of the buffered paper.

fgorga said:

Superior in what way?

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From an archival point of view perhaps. Apparently, acid-treatment of non-rag papers introduces pulp acids or so I gathered in a Altphotolist thread.

jda said:

Thanks for your reply,
I have a history of using 100% rag papers with pt/pd, so I'm cautious of cellulose paper.

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This is one of my pet peeves on definitions. Provided your paper "rags" are all cotton, they are also nearly pure cellulose. Here's the Google AI:




AI Overview




Yes, cotton is almost pure cellulose (90–95%), making it the purest natural form of this polymer. It is a renewable, biodegradable carbohydrate comprising long, linear chains of glucose units, which provide strength, durability, and high absorbency to the fiber.

jda said:

That's why I questioned the Canson Edition paper against the Canson XL watercolor which is cellulose.

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Both cellulose, just from difference plant sources with different impurities.

jda said:

I'm ordering some Canson XL to try it.
I have the "Massive Paper Chart". Maybe I missed some information there.. It's hard to know how much calcium carbonate is in each paper with regards with how to treat it.

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Calcium carbonate, which is normally called "chalk" is not soluble in water and is dispersed in paper as little particles of nearly inert material. It reduces water absorbtion and physically strengthens the paper. Chalk will react with strong mineral acids, but is nearly inert to the milder organic acids used in alt processes for the most part. In art papers, it acts as a buffer to absorb acids. Since not water soluble to any degree, it doesn't affect the Ph of the paper unless a strong acid is present. Hence the acid free designation.

jda said:

Also, doesn't that 15% vinegar wash bleach your fine highlight detail?

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No, cyanotypes are bleached by basic solutions, not acidic solutions. The vinegar reduces the contrast of the cyanotype slightly while oxidizing the Prussian blue similar to hydrogen peroxide, so it strengthens the tones.

That's a very compete

cirwin2010 said:

I can't speak to fgorgas vinegar wash, but I acidify the paper in 10% sulfamic acid until it stops fizzing (about 25-30 min) then give it a thorough wash.

The surface layer stops bubbling really quick in the sulfamic acid, but it takes much longer to neutralize the center of the paper fibers. Small jets of bubbles will appear at the paper edges after a while.

Click to expand...

Thanks for the info.

Alan Townsend said:

This is one of my pet peeves on definitions. Provided your paper "rags" are all cotton, they are also nearly pure cellulose. Here's the Google AI:




AI Overview



View attachment 419965
Yes, cotton is almost pure cellulose (90–95%), making it the purest natural form of this polymer. It is a renewable, biodegradable carbohydrate comprising long, linear chains of glucose units, which provide strength, durability, and high absorbency to the fiber.


Both cellulose, just from difference plant sources with different impurities.


Calcium carbonate, which is normally called "chalk" is not soluble in water and is dispersed in paper as little particles of nearly inert material. It reduces water absorbtion and physically strengthens the paper. Chalk will react with strong mineral acids, but is nearly inert to the milder organic acids used in alt processes for the most part. In art papers, it acts as a buffer to absorb acids. Since not water soluble to any degree, it doesn't affect the Ph of the paper unless a strong acid is present. Hence the acid free designation.

No, cyanotypes are bleached by basic solutions, not acidic solutions. The vinegar reduces the contrast of the cyanotype slightly while oxidizing the Prussian blue similar to hydrogen peroxide, so it strengthens the tones.

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Thank you for the detailed response Alan.

I had not previously considered that they are both cellulose, but your explanation makes sense.

I am always open to new information, even when it challenges my current perception.

Alan Townsend said:

Since not water soluble to any degree, it doesn't affect the Ph of the paper unless a strong acid is present.

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This is not strictly true; calcium carbonate has very low solubility in water - and that's pertinent in this case as it does in fact result in a little bleaching of a cyanotype printed on calcium-carbonate buffered paper. This can be observed by making the same print on the buffered paper and paper where the buffer was removed; the print on the buffered paper will have a slightly different hue (tending a bit towards magenta) and moreover, the most delicate highlights will be bleached back a little.

Alan Townsend said:

is nearly inert to the milder organic acids used in alt processes for the most part.

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If this were true then buffer neutralisation with Citric Acid wouldn't have worked. But it does work.

Raghu Kuvempunagar said:

If this were true then buffer neutralisation with Citric Acid wouldn't have worked. But it does work.

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I did use the term "nearly". I do not wish to look up the references on the Cyanomicon on this, but Ware elaborates on this subject quite a bit. Ware makes the statement many times about mineral acids required to dissolve chalk.

My crude understanding, which may be wrong, is that most weaker organic acids like citric, tartaric, acetic and others form complexes with chalk that remain in the paper. So they do have an effect, but more like a surface effect on the little grains of chalk that coat them and then change the behavior. However, the chalk is not removed, which is partly good. Removing all the chalk greatly reduces the strength of the paper.

A few years ago, I experimented with removing all the chalk in some water color papers using fairly strong (10%) muriatic (hydrochloric) acid. After an hour soak, the paper is so weak it almost falls apart when removed from the tray. After drying, it's so porous it can't be used without sizing several times. My point is that removing too much chalk can be as bad or worse than not removing enough.

I believe all we need is to remove or neutralize a certain amount of chalk that is near the surface on the side we are coating. I remember the long thread here on Photrio on using sulfamic acid soaks of various strengths for various times. Much discission on how strong and how long. Five percent and five minutes sounds good to me, but now many have increased this greatly for unknown reasons. If you recall, I use a lot of citric acid in my sensitizer, and this remains in the paper until developed,, but also only effects one side of the paper. Yes, this also helps with the chalk problem. So does a little citric acid in the wash water.

I plan on experimenting with the ferroblend process soon, and plan on using a few ml of a 5% solution of muriatic acid on one side of that paper coated just like the sensitizer, left in place for about five minutes, and then washed out. This should limit the damage to a thin layer on one side of the paper yet be effective at doing the good things we need. I think there is too much fear about the chalk removing, or acidifying the paper subject. I approach this from the direction of removing as little as I can while still getting the results I want. This conserves time and materials.

Alan Townsend said:

most weaker organic acids like citric, tartaric, acetic and others form complexes with chalk that remain in the paper.

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I'd expect that citric acid with calcium carbonate will just become calcium citrate and carbon dioxide. Calcium citrate is moderately soluble in water and I'd expect sufficiently so to mostly wash away. Even if it doesn't, the carbonate is still gone at this point and I don't expect that the lingering citrate will do much harm.
From a more practical viewpoint I can only conform what @Raghu Kuvempunagar also said, i.e. that citric acid does appear to work to remove or at least very dramatically reduce the alkaline buffer from a paper. I guess ultimately that's what counts.
Whether or not this only happens on the surface, I don't know, but I do understand the logic that we may only have to avoid the carbonate from getting close to the image layer esp. during the time the paper is wet. However, given the marginal solubility of calcium carbonate and the sensitivity of Prussian blue to any amount of carbonate, I would expect that also remaining carbonate deeper in the fiber mat would present problems with bleaching if they remained in the paper.
And I honestly doubt citric acid couldn't get there while at the same time removing it at the superficial layers of the paper.

Organic acids will neutralize CaCO3 - take some chalk powder and drop it into citric, acetic or oxlaic acid. While calcium citrate (less) and calcium acetate (quite a bit) are water soluble as @koraks pointed out, calcium oxalate (think kidney stones) is not so it stays in the paper. Calcium sulfamate is highly soluble so it will come out easily when washed after treatment.

Secondly, the acid treatment also takes out some of the sizing agent such as gelatin (it's ph dependent) as well as perhaps other additives - that also makes the paper more porous as well as more hydrophilic. That in itself can also affect the outcome of the process.

In other words, it is complicated.

:Niranjan.