Cyanotype highlights

Hello! I would like to ask for some help, hoping you might have a solution to a seemingly simple problem. I can't seem to make the highlights completely white on my cyanotype paper.

Here are some important details to know:

• I'm using the classic combination of 12 grams of ferric ammonium citrate and 5 grams of potassium ferricyanide.
• The paper is a very nice 50% cotton Fabriano, which is supposed to be acid-free and seemed perfect in all other aspects to me (I should mention that I've had the same issue with other papers as well).
• It's not an issue with the exposure because I've tried developing the coated paper without any exposure.
• I develop the paper in slightly acidic water (nitric acid), then rinse it with plain water, and finally, in a very mildly acidic water for a few minutes.
• I've noticed that freshly mixed cyanotype solution adheres to the paper less, but even after trying various methods, I still have some shades remaining.
• If possible, I don't want to bleach the paper or tone it; I like the blue color as it is.

Do you have any ideas or suggestions?

I've had excellent highlights using Mike Ware's "New Cyanotype" process. https://www.mikeware.co.uk/mikeware/New_Cyanotype_Process.html

Results: https://www.photrio.com/forum/media/clover-cyanotype.17903/

turtleandrabbit said:

• It's not an issue with the exposure because I've tried developing the coated paper without any exposure.

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Just to make sure I understand, if you coat the paper and dry it per normal conditions and develop it without any deliberate UV exposure, you get blue stain/fog all over the paper?

:Niranjan.

nmp said:

Just to make sure I understand, if you coat the paper and dry it per normal conditions and develop it without any deliberate UV exposure, you get blue stain/fog all over the paper?

:Niranjan.

Click to expand...

Yes, it's very subtle and don't get me wrong, with a fresh mix it's almost indistinguishable from the papers white, but it's there.

turtleandrabbit said:

Yes, it's very subtle and don't get me wrong, with a fresh mix it's almost indistinguishable from the papers white, but it's there.

Click to expand...

There are several possibilities of how one can end up with blue stains on the paper without being exposed. It could be due to a) paper is interacting with the chemistry somehow reducing the ferric and making some Prussian blue, or b) your FAC is somehow compromised with ferrous resulting in Prussian blue which may not be a lot to notice in the solution but enough to be deposited on paper on drying (does the coating look bright yellow or is there a hint of green in it?) and finally c) there may be an inadvertent exposure to some UV from the ambient while it is being dried or stored before exposure (review your procedure.)

Of course, there are more potential sources of stain/fog along the way as you go though rest of the the process. Would you say in the end the blue density you get at the densest part of the negative is similar to that obtained without exposure or significantly greater? What kind of negative are you using?

:Niranjan.

turtleandrabbit said:

Yes, it's very subtle and don't get me wrong, with a fresh mix it's almost indistinguishable from the papers white, but it's there.

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In my experience, it sounds like it’s the paper. I dug into my paper supplies and coated water color papers, drawing papers, wrapping papers, etc., dried in the dark and then developed these samples. The brown wrapping paper had already gone blue. The others varied. Since I tend to draw on the cyanotype after it’s processed and dried, I prefer the tooth on Stonehenge drawing paper and I get good, clean whites with that. Also, as mentioned above, the new Mike Ware formula gives good results and is what I use. It’s a bit more work to mix up but superior results. You might also want to check out the book:

Cyanotype: The Blueprint in Contemporary Practice (Contemporary Practices in Alternative Process Photography) 1st Edition​

by Christina Anderson

I picked it up at my local library and it’s a wealth of information with lots of data on papers.

Here’s a portion of a cyanotype with a drawing I did. The whites are quite good in the cyanotype. The paper white was left in the drawing portion.

As usual, it is hard if not impossible to say what is going wrong in the printing process without seeing the negative.

A scan of the cyanotype 'fog' on unexposed paper compared to the virgin paper would also be a help.

My gut feeling is that you're either getting some fogging due to UV light exposure while it should be drying in darkness, or it's actually just staining from the washing process (blue comes out of other areas of the paper and settles into the fibers where it would otherwise have remained pure white).

I only have firsthand experience with Mike Ware's new cyanotype, but my staining is in the range of "minimal to none" and I have no fogging with Hahnemuhle Platinum Rag.