Hostile cyanotype enviroment

[WillL]

Loris, thanks for your specifics on the various papers. I'm not trying to be argumentative here, just trying to get accurate information about this subject. Can you tell me how you know the specific papers you mention are non-buffered in their current production runs? Canson's website has product specifications and they now say that Montval watercolor paper IS buffered. I've contacted Fabriano twice in the last year asking for information about which of their products are buffered and they refuse to provide this information. Can't imagine why they won't answer this simple question? Even though a paper mill tries to achieve a consistent supply of raw materials, I wonder if different batches of paper pulp and fiber have differing ph levels that require varying amounts of buffering levels to achieve archival stability. Maybe this would account for the often repeated accounts of papers that work great in one printing session and then quit behaving well when they're from a different manufacturing run? We buy the Arches Aquarelle mainly in 51" x 10 meter rolls, usually ten or twelve rolls at a time. I definitely notice differences in paper color and printing behavior from batch to batch. Sometimes the paper is very consistent and sometimes I have to throw away 50% of the prints I make depending on any given roll.

[Loris Medici]

WillL, it's empiric information: they all print well with Cyanotype? (That's our actual subject right?) BTW, some print well with Argyrotype and New Cyanotype too - the most finicky processes when it comes to paper choice... In any case, a 1-3% HCl bath for 2-5 minutes and a good rinse (3-5 water changes, 10-15 minutes...) will take care of calcium carbonate buffer for sure, BUT with the expense of decreasing the paper's longevity. (By the action of HCl severing some bonds within the cellulose structure - the longer the treatment, the more serious the damage will be.)

Can't you request a sample from the batch, before committing for such a big amount of (155 square meters; equiv. to 155 A0 / 620 A2 sheets!!!) paper?

Regards,
Loris.

[WillL]

You are so right about the New Cyanotype chemistry being finicky about paper! I have successfully printed traditional cyanotypes on several papers I know are internally buffered though. Not sure why some work and others don't though. Maybe the internal buffering is more sequestered from the surface in some papers due to more sizing?

We do test papers in small quantities before buying larger orders, definitely. BTW, which of the papers you mentioned have you had success with using the New Cyanotype?

I had written Bergger in France and asked them about buffering in their COT 320 and heard back from them today. They say it is "internally buffered to ph 6.6 without NaOH."

[Loris Medici]

Hi WillL, Awagami Masa and Bergger COT 320 were the two papers that worked extremely well with both New Cyanotype and Argyrotype. Weston Diploma Parchment also worked OK (New Cyanotype) with only a very very faint / practically non disturbing background fog...

Regards,
Loris.

[quiver]

I found that the crayola paper works for cyanotype but it is easy to tare when wet and requires special handling. I might check the local drug store for other possible papers.