Cyanotype issue on brown craft paper

VinceInMT · Mar 29, 2021

I've been doing cyanotypes and using standard watercolor paper with good results. I have a big roll of brown craft paper so I though, "Why not?" I coated a piece with sensitizer, in the darkroom as usual, and a few minutes later it turned dark blue, not the light yellow like the watercolor paper. After it dried I put a piece out in the sun for a while with part of it covered and it did register an image, but only slightly. I tried it again after I soaked and washed a piece of the craft paper and, again, it turned blue in the darkroom. I assume that there is something in the paper that is reacting with the sensitizer. Any ideas?

NedL · Mar 30, 2021

Since you're willing to soak and dry the craft paper before using it, you could try soaking it for 10 or 15 minutes in weak acid. 1 part vinegar with 2 parts water, or a few teaspoons of citric acid in a couple cups of water might be a place to start. Good luck!

fgorga · Mar 30, 2021

Once, many years ago, I experimented with making cyanotypes directly on wood panels. It was not particularly successful.

On most types of wood the sensitizer reacted as you have seen with the Kraft paper, it turned blue without exposure to light.

There were a few types of wood where this reaction was slow enough that I could actually make an image even though the highlights were stained. I'm not sure that I tried hard enough, but I never made an image I thought useful.

My chemical background leads me to think that any material containing lignin is likely to be problematic for cyanotype. Wood pulp is a mixture of two polymers, celluose and lignin. Lignin is the reason cheap paper (e.g. newsprint) yellows upon exposure to air and light. This yellowing is due to photo-oxidation of the lignin. Thus, I suspect that lignin, being redox active, is the culprit with respect to cyanotype.

Since Kraft paper is made from a fairly unrefined grade of pulp, I am not surprised with your result. It can't hurt to try pre-acidification as NedL suggests, however, if the problem is lignin it won't help things.

nmp · Mar 30, 2021

Kraft paper does not contain buffering agents, as far as I know, so the acid treatment probably not work in the same way as it does on common watercolor papers. But then you never know.

If lignin is the culprit, it being a reducing agent producing ferrous ions prematurely, then would hydrogen peroxide (in acidic medium) pre-treatment work? Kind of pre-empting lignin's reductive powers before it can do damage to the cyanotype sensitizer. (Incidentally that's how they "delignify" kraft paper to make white paper. )

:Niranjan.

BJ68 · Mar 31, 2021

nmp said:
If lignin is the culprit, it being a reducing agent producing ferrous ions prematurely, then would hydrogen peroxide (in acidic medium) pre-treatment work? Kind of pre-empting lignin's reductive powers before it can do damage to the cyanotype sensitizer. (Incidentally that's how they "delignify" kraft paper to make white paper. )
.

Depends if you can reduce the power to an amount, where this "dark reaction" is so slow, that it does not disturb.

Other possibility would be to size the paper with gelatin or use Variant 1 (with 4% gelatin in Solution A) from https://illumina-chemie.de/viewtopic.php?p=72786#p72786
Further the glutaraldehyde can be omitted for simplifying the recipe further. The stability of both solutions are good see Retest under https://illumina-chemie.de/viewtopic.php?p=78036#p78036 although the coating behavior of the emulsion looks strange....

bj68

removed account4 · Mar 31, 2021

I've printed cyanotypes on brown paper bags and from craft paper off of a roll
never had problems like you describe, unless it was really humid, the humidity from the air did as you described.

fgorga · Mar 31, 2021

nmp said:
Kraft paper does not contain buffering agents, as far as I know, so the acid treatment probably not work in the same way as it does on common watercolor papers. But then you never know.

If lignin is the culprit, it being a reducing agent producing ferrous ions prematurely, then would hydrogen peroxide (in acidic medium) pre-treatment work? Kind of pre-empting lignin's reductive powers before it can do damage to the cyanotype sensitizer. (Incidentally that's how they "delignify" kraft paper to make white paper. )

:Niranjan.

Hmmm... interesting idea!

Maybe I'll have to give cyanotype on wood panels another try. Yippee... more experiments!

fgorga · Mar 31, 2021

jnantz said:
I've printed cyanotypes on brown paper bags and from craft paper off of a roll
never had problems like you describe, unless it was really humid, the humidity from the air did as you described.

Now that you mention it, I use brown paper grocery bags to protect my work surface when I coat cyanotypes. If I get sensitizer on the brown paper, it does not turn blue until it has sat for awhile exposed to light.

VinceInMT · Apr 3, 2021

Just a followup...I just coated 4 pieces of paper with cyanotype sensitizer. See the photo. The one on the left is watercolor paper. Moving to right the next one was plain untreated craft paper, then craft paper that I'd soaked in citric acid, and finally, on the right, one that I'd soaked in hydrogen peroxide. I let them dry in the dark and then took this photo. I guess I won't be using the craft paper for this project. I have lots of watercolor paper and Stonehenge so I'll stick with those.

Thanks.

fgorga · Apr 4, 2021

Well, that seems pretty definitive! Thanks for reporting back.

I think you've got the right idea... sometimes in alt processes it is just not worth fighting with the paper!

Stonehenge is a good choice, the warm variety is one of my favorites for both cyanotype and salted-paper.

Do you know that Stonehenge comes in a variety of colors, including "kraft", see https://www.acuitypapers.com/Stonehenge-Paper-p/119-0060.htm.

I have not tried any color but white, warm and cream for cyanotype. Those all work.

Maybe a colored Stonehenge would allow you to achieve your initial vision.

nmp · Apr 4, 2021

VinceInMT said:
Just a followup...I just coated 4 pieces of paper with cyanotype sensitizer. See the photo. The one on the left is watercolor paper. Moving to right the next one was plain untreated craft paper, then craft paper that I'd soaked in citric acid, and finally, on the right, one that I'd soaked in hydrogen peroxide. I let them dry in the dark and then took this photo. I guess I won't be using the craft paper for this project. I have lots of watercolor paper and Stonehenge so I'll stick with those.

Thanks.

it Isn't (and won't be) the first time, the cyanotype serves up exactly the opposite of what you thought might or should happen.... But it's good to know. Paper might be the most complicated part of making cyanotypes on which we have the least insight or control, ironically.

Thanks for the update.

:Niranjan.

VinceInMT · Apr 4, 2021

fgorga said:
Stonehenge is a good choice, the warm variety is one of my favorites for both cyanotype and salted-paper.

Yes, and my favorite for drawing. Here's 2 of my recent ones.

NedL · Apr 4, 2021

fgorga said:
Now that you mention it, I use brown paper grocery bags to protect my work surface when I coat cyanotypes. If I get sensitizer on the brown paper, it does not turn blue until it has sat for awhile exposed to light.

And seeing this made me remember something else. I have a stack of cut pieces of cardboard that I sometimes tape paper to when coating. Early on I discovered that if you coat cyanotype heavily, the paper will prematurely blue/green where the moisture interacts with cardboard. I think what fgorga wrote about lignin sounds reasonable. I went and bought some "dollar store" plastic cutting boards and have been using them for cyanotype ever since.

Cyanotype issue on brown craft paper

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