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Relative Humidity and New Cyanotype

4LivingWage

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Mar 25, 2023
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21
Location
Houston
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DSLR
I have started playing around with Ware's New Cyanotype. I made up my own solution with chems from Artcraft. I found, after letting the brown bottle lie for a couple of days, there was about a tsp full of green crystals on the bottom which I discarded. I then filtered the rest back into the clean brown bottle. I have been getting an excessive amount of grain and brush stokes showing up in prints which had not been a problem with classic cyanotype. Can relative humidity in my environment (around 55-57%) be a culprit? Also, I apply sensitizer on arches platine taped on plexiglass and I dry it while taped. Could this be causing improper drying?
 
Could you show some photos?
What's the color of the sensitizer? It should be emerald green and the paper coated with it should be a fairly pale lime color; if it's cyan or blue, it has solid Prussian blue pigment in it which may remain stuck in the paper and survive processing.

Having said that, by far the most of the problems with New Cyanotype are due to incompatibility of the paper with this finicky chemistry. With some papers it helps to pre-soak them in an acid bath to remove the carbonate buffer from the paper; then re-soak in plain water to get rid of most of the acid.

Other contributing factors to streaking can be rheology and interactions with the application method (brush technique, choice of brush) and the surface characteristics of the paper. It can help to add a little surfactant (tween, photoflo) to the chemistry, although in my experience this can also introduce new problems.

Classic cyanotype overall is more robust and easier to work with. Unless there's a compelling reason to use New Cyanotype, I'd steer clear from it, to be honest. So many people have trouble with it. If you want to deviate from the classic formula, I'd give Simple Cyanotype a try.
 
Paper leans heavily toward a green, maybe even chartreuse. IK notice some crystals on print after exposing, these must contribute to the graininess. The fact that I dried paper on the plexiglass sheets may have lead to an imperfect drying underneath. Just a thought. I will post a scan tomorrow. I was wondering whether thre relative humidity were an issue at 55%
 
RH is not likely to be an issue here.
Try some different papers, or acid-soak this paper as described above. This is a finicky process when it comes to paper. Papers that work well with regular cyanotype do not necessarily also work with New Cyano.
 
You might want to check in the massive paper chart if your paper is compatible with New Cyanotype and if acidification is needed.

If crystals formed on the paper after exposure, try diluting the sensitiser 1+1 with distilled water.

If the sensitised paper turned darker after drying, try adding Citric Acid to the sensitiser at the time of costing.

If you suspect inadequate drying at room temperature, use a hair dryer for 5 minutes.
 
Shouldn't the coated paper lean more towards lemon yellow than green - the latter could mean you already might have some Prussian blue or perhaps more than usual residual K ferrio-oxalate (which can impart greenish shade) in the mix. The latter can re-crystallize on the paper and give a gritty look. Try cooling the liquid for some time to force more of it out of the solution and filter again.

:Niranjan.
 
Jumping in as I've now had a lot of recent experience with Mike Ware's new Cyanotype. Like other posters are saying, it is very paper dependent and it seems not everyone's experience with the same papers line up from my testing.

I will go against the grain here and say that humidity IS an important factor. Specifically the humidity of the paper. I am currently working in very dry RH humidity conditions between 30-35%. This can make paper less absorbent to the solution causing uneven coating and distribution within the paper sizing and fibers.

With the papers I have tested thus far, I have found that humidifying the paper to be a must with new cyanotype under my conditions. Coating dry paper leads to scratchy, splotchy, and/or gritty results with new cyanotype. Pre-humidifying the paper for a few hours (or longer) before coating solves this problem. I then let the paper completely dry before exposure.

Paper that poorly absorbs the new cyanotype solution also tends to form crystals on the surface after drying (looks sparkly). This can adhere to your negatives and ruin them. I have also found that with certain papers like Legion Revere Platinum (coated dry), after processing the prussian blue will just sit atop the surface of the paper giving it a chalky texture that can rub off on your fingers.

Regarding color when applied, new cyanotype will be a yellow-green color where classic cyanotype just looks yellow. Certain paper will appear more green than others. As long as it is not a green-blue you should be fine.

I have found that the best paper for new cyanotype to be Canson XL Watercolor after being soaked in a 10% sulfamic acid bath to clear the buffering and neutralize/acidify the paper. Then I humidify the paper prior to coating and apply a single coat. About 2ml for an 8x10" area using a brush. This gives excellent results.

To pre-humidify my paper, I fill a try with water, lay some screen across it to hold my paper, then clamshell it with another try on top. Depending on the temperature 1-2 hours my be needed for thicker paper.

See my recent cyanotype thread to witness my failures and successes with this process.
 
I used Arches Platine and COT 320. Both are deemed perfect as is by Christina Anderson's tests. I do not pre-acidify per her comments. So, paper should not be an issue. The sensitizer is yellow when I first coat and then turns a greenish yellow after drying. Last batch I dried it on a screen, then, after moved it to an archival cardboard box to dry overnight. This morning I printed one of the Arches Platine for 12'30" in my UV box with 7 Barrina lamps that are about 8 inches from the print frame. After exposure, I noticed shiny speckles on the print before washing. I developed in fresh water, then a 5% HCI bath twice, a 1.5% Citric Acid bath, a spritz of Hydrogen Peroxide, and a 20-minute wash. I will post the print once it dries.

RH in my environment is between 52 and 58%. I live in Houston, but my house has central AC and is kept at ~72 degrees, so the environment really should not be a factor. If it is, then this process is just too finicky for my taste. I have been having conversations with ChatGPT and Claude about this for several days as well as researching on the net. I feel like we're becoming best friends!! Not my idea of a good time, but the GPT's prove helpful eliciting my own questions, thoughts and observations and have made some interesting observations about my Curve. So, not a waste of time by any stretch. I just might summarize and post the commentary as it might prove useful.

Appreciate your help. I will post images later after drydown.
Incidentally, I have done Classic Cyano and Kallitype and have not had any of these issues-no problems with brush strokes showing, graininess, etc. So I don't think my mechanical workflow is problematic.
 
4LivingWage said:
used Arches Platine and COT 320. Both are deemed perfect as is by Christina Anderson's tests. I do not pre-acidify per her comments. So, paper should not be an issue.
Click to expand...

Have you tried (acidifying)? You may be pleasantly surprised.
 
With fresh out of the box paper, like HPR, and Revere P., I like to give them a pre-soaking in distilled water, then hang up to dry. I find the papers take the sensitiser more readily. In regards to RH, if my darkroom is over 60RH, on goes the dehumidifier! High humidity will work against you!
You may want to mix up some traditional Cyanotype, and see if it works. I always found Ware's New Cyanotype to be a bit finicky... and eventually went back to traditional version. Give it a shot!
 

I have had no problems with classic cyanotype. Sometimes I should leave well enough alone but i wanted to try the new cyanotype, and now I'm spending a week solving these problems! I will hang it up if I cannot lick it quickly. Thanks for the advice.
 
As promised, here are two prints I made. You can see clearly the effects of the crystals. On #1 you may be able to see the brush strokes. That is on the Arches Platine. The #2 is dark, admittedly, and is on COT320. I don't find the brush strokes apparent, but do see the crystals. I poured the sensitizer on both and then brushed it as easily as I ever have. Any observations from your experience appreciated. Thx Dennis
 
This looks a lot like crystal formation to me.
Since you already work with the classic formula, you might want to try a 50/50 mix of new and classic, as it eliminates the crystallization issue. A few well known alt printers use this hybrid approach - Sam Wang comes to mind.
 

I cannot find any references to this approach. Are you pulling my leg?
 
This looks to me like it might be an issue with his the paper fails to absorb the sensitizer. Things you could try:
* Dilute the sensitizer a bit
* Add some surfactant
* Soak the paper in plain water, then dry it and try coating again.
Sometimes it's also as simple as trying the backside of the paper, as both sides often show differences in rheology.
 
I added a drop of tween 20 to about 40 drops of sensitizer. I tried several papers, I will try diluting the sensitize a bit.
 
4LivingWage said:
I have had no problems with classic cyanotype. Sometimes I should leave well enough alone but i wanted to try the new cyanotype, and now I'm spending a week solving these problems! I will hang it up if I cannot lick it quickly. Thanks for the advice.
Click to expand...

There are two main drawbacks of New Cyanotype process over Classic Cyanotype:

1. It doesn't work well in the presence of some paper additives including the buffer. Fortunately, preacidification of the paper (even unbuffered paper) mitigates this issue to a large extent.
2. The process to remove Ferric Potassium Oxalate (green crystals) from the sensitiser is not perfect and depending on the conditions, there is always some residual Ferric Potassium Oxalate in the sensitiser which leads to crystal formation during exposure. Diluting the sensitiser does help in reducing the chances of crystal formation during exposure. This comes at the expense of somewhat reduced DMax which might be acceptable.


Adding Ferric Ammonium Citrate to the sensitiser a la Sam Wang does address the crystal formation problem but then the process is no longer New Cyanotype.
 
You have already gotten some good advice.

Regarding your first question; I don't think the humidity is a problem in your dimroom. 45-65% should be just fine.

It looks like the paper isn't absorbing the sensitizer well enough or evenly enough.

I would start by brushing the paper with distilled water (or 0.25% sulfamic acid). Not too much, you don't want it to be soaked. Hang the paper a few minutes, at least until the surface is matte, and then coat it with sensitizer. Keep brushing lightly until there are no puddles.

If that isn't enough to solve the issue I'd also add some more Tween.

And I would dip the brush in sensitizer before it touches the paper (may not be necessary, but has solved some problems with uneven coating).

Can you use a slightly smaller volume of sensitizer and still cover the paper? Maybe some sensitizer is drying before it's absorbed by the paper?

I don't use NC myself, but something closer to what PGum is suggesting. Or CC most of the time.

Good luck!
 
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Raghu Kuvempunagar said:
Adding Ferric Ammonium Citrate to the sensitiser a la Sam Wang does address the crystal formation problem but then the process is no longer New Cyanotype.
Click to expand...

Raghu, that is certainly true. A chemistry purist might consider it a hack, but if the objective is a well behaved sensitizer + high quality images, it might be worthwhile to attempt.
 
4LivingWage said:
I cannot find any references to this approach.
Click to expand...

Additional references:

Christina Z. Anderson, Cyanotype: The Blueprint in Contemporary Practice , Page #224, Chapter #15.

"new cyanotype + classic cyanotype (15%–25%fac:10%pf ) mixed 1:1 just prior to coating."

https://www.facebook.com/
 
I added 10 mls of distilled water to what was left of my solution, about 50 mls. I will try this out on Arches Aquarelle. If that causes problems, I will try the 50-50 solution and then compare it to straight Classic. I will report back and many thanks to you all for the help.
 
Chapter 7 in Christina Anderson's book goes into detail about Sam Wang's formula. This is interesting and thanks again for enlightening me. I will experiment a bit with it.
 
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