Stability of Paper Coated for Cyanotype

[fgorga]

I know that this topic (ie. the stability of coated, but unexposed cyanotype paper) comes up periodically, so here is another more-or-less random observation on the topic.

I just discovered (tucked into the pages of my cyanotype log book) a sheet of Stonehenge Warm paper that I coated with traditional cyanotype sensitizer on 15 Nov 2020 (i.e. about a month ago). This sheet of paper looks identical to paper I coated this morning.

I've tucked the sheet back into my log book to continue the "experiment" so I can't say how it would print, but I can't image that it would not work well.

 

[joshuauaua]

I'm keen to know how it goes. I've had sheets that have been sitting for two days that didn't expose a thing, but then they had fallen on the floor and forgotten about and perhaps been exposed to uv in the meanwhile

 

[fgorga]

I'm keen to know how it goes. I've had sheets that have been sitting for two days that didn't expose a thing, but then they had fallen on the floor and forgotten about and perhaps been exposed to uv in the meanwhile

Well, I just checked my accidental test sheet and it still looks good although I do not have a freshly coated sheet to compare it with at the moment.

You say you have two-day old sheets that did not work. What color were they before exposure?

In my experience when good paper goes bad it changes color turning green and finally bue as prussian blue is made either by exposure to low levels of light or by some non-light driven reduction of iron.

The latter, I imagine, is due to reactive compounds in paper. Some papers "go blue" in the absence of light quite quickly, others (such as my sheet of Stonehenge Warm) change very slowly.

 

[fgorga]

I just came to my "experimental" sheet of paper coated for cyanotype again. (I had forgotten about this experiment, but the sheet fell out of my log book when I picked it up just now!)

It has been about three and a half months since I coated the sheet of paper and it still looks very good. There is just a bit of discoloration in one place along the very edge of sheet. The bulk of the sheet is still a nice yellow.

 

[nmp]

I just came to my "experimental" sheet of paper coated for cyanotype again. (I had forgotten about this experiment, but the sheet fell out of my log book when I picked it up just now!)

It has been about three and a half months since I coated the sheet of paper and it still looks very good. There is just a bit of discoloration in one place along the very edge of sheet. The bulk of the sheet is still a nice yellow.

It would be interesting if you follow along with "developed" piece of the paper vs time and see if any fogging shows up.

:Niranjan,

 

[Nicholas Lindan]

Engineering and architectural drawings were reproduced as blueprints (the real ones, all blue with white lines) - identical to cyanotypes. The unexposed paper was good for years if kept dry and in the dark. The processed prints are limited by the life of the paper. Use a papyrus base and bury your work in the Egyptian desert and it's good for 4,000 years.

The original blue print process was dropped in favor of "blue lines" early in the 20th century. These were all white with blue lines. Blue lines are developed with ammonia vapor. The reason blueprints were dropped is speed: a 34x22" blue line took only seconds to make. The downside is blue lines will fade with time.

 

[fgorga]

It would be interesting if you follow along with "developed" piece of the paper vs time and see if any fogging shows up.

:Niranjan,

Right now, all I have is the one sheet that I have save by accident. My thought is to use this saved sheet to exposure this sheet the next time I do cyanotype (whenever that might be... I'm concentrating on salted-paper prints at the moment).

 

[fgorga]

Engineering and architectural drawings were reproduced as blueprints (the real ones, all blue with white lines) - identical to cyanotypes. The unexposed paper was good for years if kept dry and in the dark. The processed prints are limited by the life of the paper. Use a papyrus base and bury your work in the Egyptian desert and it's good for 4,000 years.

The original blue print process was dropped in favor of "blue lines" early in the 20th century. These were all white with blue lines. Blue lines are developed with ammonia vapor. The reason blueprints were dropped is speed: a 34x22" blue line took only seconds to make. The downside is blue lines will fade with time.

Nicholas,

Can you cite evidence for your statement "The unexposed paper was good for years if kept dry and in the dark."?

In my experience, the stability of unexposed cyanotype paper varies all over the place, depending on the paper. I have coated some paper that starts to look greenish after less than 24 hours. Many papers seem to stay nice lemony yellow for quite a bit longer.

The piece of paper I mention in this thread is just a happy accident... one sheet of one paper that got tucked away in the dark by accident. I mentioned it here because the topic "how long does coated paper last" comes up occasionally and I thought that I could add a bit of anecdotal evidence on the subject. I make no claims to generality.

Personally, I try to use sensitized cyanotype paper within about 48 hours of coating just to be on the safe side.

Some papers print just fine when they are a bit greenish and other papers, that look similarly when unexposed, show significant staining in the highlights.

In my experience, one can not make a blanket statement about these matters.

 

[Nicholas Lindan]

an you cite evidence for your statement "The unexposed paper was good for years if kept dry and in the dark."

That's for commercial blueprint paper - not the stuff you make yourself.

Commercial blueprint paper maybe hard to find. But there is "Sunprint" paper if you want something that lasts for more than a few days. There are all those cyanotypes made in beer cans left outside to take a picture of a year's worth of the sun arcing across the sky. If your paper is going belly up in a matter of days something's wrong.

 

[Máx Arnold]

the topic "how long does coated paper last" comes up occasionally and I thought that I could add a bit of anecdotal evidence on the subject

Oh God, Oh God...
Personally, I like chemistry, and I don't use the traditional iron salt for my cyanotypes. I use, I pressume, Ammonium Ferric Oxalate, and it fogs in the dark in a matter of minutes. I could tell because in camera exposures of half an hour had significant base fog. Cyanotype paper can last very long if cared correctly, mine just doesn't.
As Niranjan says, it'd be interesting if you could try strips from that sheet of paper and test the fog level. One strip at a time every a couple of months should make a nice graph.
I think the reason why it's "lasting" so long is because you're keeping it on a book. All the pages around it make it almost impossible for natural light to reach it, and the only problem you could have comes from chemicals on the paper touching the surface of your sheet. I say this because that's how I store my chlorophyll anthotypes, and so far they've lasted two years and a half, remaining in the same condition I left them. (if you know anthotypes you'll see they're very prone to fade)
I know it's not your intention, but if you do try to develop that sheet one strip at a time, please post it! <3

 

[fgorga]

That's for commercial blueprint paper - not the stuff you make yourself.

Commercial blueprint paper maybe hard to find. But there is "Sunprint" paper if you want something that lasts for more than a few days. There are all those cyanotypes made in beer cans left outside to take a picture of a year's worth of the sun arcing across the sky. If your paper is going belly up in a matter of days something's wrong.

Nicholas,

I think what we have here is a failure to communicate... read the first paragraph of your original response again. It is all written in the past tense, and in my reading refers to the historic "blue print" (i.e. cyanotype) process that was, as you say, phased out before the second world war. No where in that paragraph to you use the present tense which might suggest that you were referring to contemporary "sunprint" paper.

As for contemporary commercial cyanotype paper, I have no experience with it so I can't comment about it.

As for my own experience, I repeat... the stability of coated cyanotype paper (I use only the traditional sensitizer) depends greatly on the paper one uses.

I have tried papers (made from unusual fibers) that turn blue instantly upon coating. I have used papers that turn greenish overnight. There is nothing "wrong" here, it is a consequence of pushing the limits occasionally. I typically use high quality rag papers that are quite stable when coated (as this one example shows).

 

[fgorga]

Oh God, Oh God...
Personally, I like chemistry, and I don't use the traditional iron salt for my cyanotypes. I use, I pressume, Ammonium Ferric Oxalate, and it fogs in the dark in a matter of minutes. I could tell because in camera exposures of half an hour had significant base fog. Cyanotype paper can last very long if cared correctly, mine just doesn't.
As Niranjan says, it'd be interesting if you could try strips from that sheet of paper and test the fog level. One strip at a time every a couple of months should make a nice graph.
I think the reason why it's "lasting" so long is because you're keeping it on a book. All the pages around it make it almost impossible for natural light to reach it, and the only problem you could have comes from chemicals on the paper touching the surface of your sheet. I say this because that's how I store my chlorophyll anthotypes, and so far they've lasted two years and a half, remaining in the same condition I left them. (if you know anthotypes you'll see they're very prone to fade)
I know it's not your intention, but if you do try to develop that sheet one strip at a time, please post it! <3

Max,

Personally, I too like chemistry... I am a retired chemistry professor!!!

I like the idea of cutting and developing strips of my sheet of paper without exposure periodically to examine the "base fog". I think I will do that instead of making a print on it as I originally planned... no promises of a timeframe though! I am currently busy a a series of salted-paper prints which is consuming my all available photography time.

Thanks to Niranjan and you for the idea!

 

[Nicholas Lindan]

Can you cite evidence for your statement "The unexposed paper was good for years if kept dry and in the dark."?...

It was still in use in the mid 70's. We used blueprints for the distribution of prints of engineering drawings where we wanted to limit reproduction. Pointless, really, they can be copied with a camera with a deep red filter. How old the pack of blueprint paper must have been, I don't know - it wouldn't have surprised me if it had a "Buy War Bonds" sticker on it. So, can I cite evidence? Yes. What a thing to ask...

How long does Sunprint paper last? The packet says use within 3 months of opening the plastic bag. I'd wager the packets last a few years just to lounge around in distribution centers and retail stores.

That the stability of unexposed cyanotypes depends on the paper is a given. Commercial cyanotype/blueprint paper is obviously made with paper that doesn't degrade the emulsion.

For DIY cyanotypes the word is to use unbuffered paper. Apparently highly buffered paper can cause developed cyanotype images to degrade. I use Bienfang 360 marker paper and haven't noticed any problems - I have cyanotypes that have hung on the wall for close on 20 years. I don't keep unexposed sheets hanging around for years so I don't know the effect of this paper's chemistry on the long term storage of coated paper. The Bienfang paper was good, then it wasn't, then it was again - I don't know the current state of affairs with the product.

 

[nmp]

It was still in use in the mid 70's. We used blueprints for the distribution of prints of engineering drawings where we wanted to limit reproduction. Pointless, really, they can be copied with a camera with a deep red filter. How old the pack of blueprint paper must have been, I don't know - it wouldn't have surprised me if it had a "Buy War Bonds" sticker on it. So, can I cite evidence? Yes. What a thing to ask...

How long does Sunprint paper last? The packet says use within 3 months of opening the plastic bag. I'd wager the packets last a few years just to lounge around in distribution centers and retail stores.

That the stability of unexposed cyanotypes depends on the paper is a given. Commercial cyanotype/blueprint paper is obviously made with paper that doesn't degrade the emulsion.

For DIY cyanotypes the word is to use unbuffered paper. Apparently highly buffered paper can cause developed cyanotype images to degrade. I use Bienfang 360 marker paper and haven't noticed any problems - I have cyanotypes that have hung on the wall for close on 20 years. I don't keep unexposed sheets hanging around for years so I don't know the effect of this paper's chemistry on the long term storage of coated paper. The Bienfang paper was good, then it wasn't, then it was again - I don't know the current state of affairs with the product.

The blueprints as practiced since the 40's mostly involved the so-called type B (and its variants) process that had both K ferricyanide and ferrocyanide and a bunch of other things that make it bleed less and be more stable. The classic formula that we all use is the type A process involving only the ferricyanide (see Mike Ware's Cyanomicon, p. 119.) So it's not an apple-to-apple comparison between the two in terms of stability.

Sunprint also seems to use a different process as I understand - it's proprietary apparently - it starts out light blue/green which bleaches in UV to white which then become Prussian blue on development. I found this reference that claims the starting compound is Berlin green and the bleached compound as Berlin White:

https://www.stevespanglerscience.com/lab/experiments/sun-sensitive-paper-experiment/

Again, two different chemistries.

:Niranjan.

 

[Nicholas Lindan]

As referenced by Niranjan Patel, https://www.mikeware.co.uk/downloads/Cyanomicon_II.pdf seems to have all the answers.

 

[Máx Arnold]

As referenced by Niranjan Patel, https://www.mikeware.co.uk/downloads/Cyanomicon_II.pdf seems to have all the answers.

Cianomicon is the most useful book ther could be about the cyanotype process, in my opinion. I remember Mike Ware mentions the addition of certain oxidizing agent to the sensitizer to prevent base fog. I personally think it could work, if there is no reaction with the other chemicals. Sodium/ Potassium/ Ammonium Dichromate are all strong oxidizing agents, so it doesn't surprise me the help with performance.
Whatever... Frank would post some base fog test and we'll see what happens. I'd then suggest the addition of a certain amount of hydrogen peroxide to the sensitizer (again, if it doesn't react!), which if we are lucky1 would stay on the paper, keeping the iron salts from reducing in-situ and would degrade into water and oxygen gas under the presence of light, so it wouldn't affect development.
1, because... it might actually evaporate like water.

I'm going to share an experience. I once took a photograph using a homemade camera of low f/ number. I exposed for a reasonable amount of time but had no way of developing the image, since I hadn't acquired the ferrocyanide salt. What I did at that time was to save it in the middle of a thick National Geographic issue, in the middle of my shelf between all the books. I am completely sure no light hit the paper whatsoever. The latent image stayed there for about ten days, until the chemical finally arrived, and when I could get that good blue, well... There was no image.
There was color, though. A very rich blue, which I never saw while printing. Also, there was no base fog, since some part of the paper remained perfectly white. I think my latent image got lost, the ions went nuts, whatever... But there was no fogging. I can report having seen turmeric anthotypes fading over time into some sort of swirly resemblance of the image, which tells me these things happen sometimes.

 

[Nicholas Lindan]

The blueprints as practiced since the 40's mostly involved the so-called type B

After reading through (well, skimming & searching) Mike Ware's book:

Engineering & architectural blueprint paper was yellow when unexposed. It is Type A by Mr. Ware's reckoning and best suited for line work. That it had all sorts of pixie dust in it I have no doubt.

Type A seems to be a spitting image of "New Cyanotype" (or vice versa): Ferrioxalate & Ferricyanide plus a pinch of Dichromate.

Type B is characterized as better suited to pictorial work and not so good at engineering drawing reproduction. B is made from Ferrioxalate & Ferrocyanide; Type C from Ferrooxalate & Ferricyanide. I can see some ordering confusion here.

Is anyone doing work with B or C?

 

[Nicholas Lindan]

There was no image. There was color, though.
View attachment 267922

That's really rather beautiful.

 

[Máx Arnold]

Type B is characterized as better suited to pictorial work and not so good at engineering drawing reproduction. B is made from Ferrioxalate & Ferrocyanide; Type C from Ferrooxalate & Ferricyanide. (...)
Is anyone doing work with B or C?

Me. I once saw a posting that used ferric sulphate and ferricyanide. I got adventurous and bought reagents for preparing ferrioxalate and also bought ferrocyanide. I just made a lot of research because I thought I couldn't use ferrocyanide, and then I realised it would work, but it actually should yield a positive image. It doesn't. It works just as well as if I was using ferricyanide. Probably, and Mike Ware says it better than me, because the berlin white formed gets quickly oxidized into prussian blue.

 

[NedL]

... There was no image.
There was color, though. A very rich blue, which I never saw while printing. Also, there was no base fog, since some part of the paper remained perfectly white. I think my latent image got lost, the ions went nuts, whatever... But there was no fogging. I can report having seen turmeric anthotypes fading over time into some sort of swirly resemblance of the image, which tells me these things happen sometimes.

See, to me, this sounds like something I might want to do on purpose! Enjoying reading this thread.