printing cyanotypes on hahnemuhle platinum rag (challenges)

[MichaelFS]

Thanks so much!

BTW- do you (or anyone on thread) recommend a good online source for Tween?

thanks again!

[jnantz]

Michael

the only 3 places I know of (besides getting a special order from a photo shop who will get it from the same place ) is Bostick and Sullivan, Artcraft Chemistry and Photographer's Formulary. You are only coating one coat of cyanotype chemistry? I used to coat with just 1 coat and the world opened for me when I started to use 2 or 3 coats.

Good luck, making cyanotypes is probably more fun than regular people like us should have
John

[MichaelFS]

Thanks John!

I've been using Bostick for years, almost the beginning, so I can order tween along with some other chems I'm low on together.
I have heard from another artist about the 2-coat application benefits, so will at least have to give it a try, even if I'm a little skeptical...

many thanks again for all your insights-

Michael

[newt]

I would use a different paper. I print Pt on HPR, but cyanotype I have had great results on Stonehenge which is available in much larger sizes too if you want to go that way.

[Alan Townsend]

I'm very new to alternative processes so I'm hoping to learn as much here as the OP. Is it necessary to acidify your paper first? I've only been working with cheaper watercolor paper from walmart until I get better at the whole thing. I do have a pack of Arches and a pack of crazy expensive Hahnemuhle 100% cotton rag to experiment with. I thought that hahnemuhle was made special for this kind of thing, I don't remember watching any videos where they acidified the paper, especially hahnemuhle. Due you use oxalic acid or citrus acid?

The watercolor paper I buy at my Walmart (Grumbacher) works very well for cyanotype witthout any pre-treatments using a 20-10 fac-pfc sensitizer, although probably not very archival since it is heavy on the chalk content. Some people use a 1% citric acid solution as pre-treatment for some papers that don't give a very deep dmax, like Strathmore 300 series papers, which I have found need this. Any watercolor paper can be soaked in an about 1% hydrochloric acid solution overnight to completely remove all chalk. This makes the paper like a limp rag, and requires many washings to remove the acidity, but may help with long term permanence. Too much work in my book as well.

Most cheap watercolor papers work quite well for cyanotypes. Save the expensive ones for your art gallery debut. I'm 71 years young and believe my cyanotypes will last the rest of my life, although that not may be as long as yours.

I foam brush my blue prints with a 1% citric acid solution after exposure to oxidize and extend the tonal range a bit, a 10% vinegar solution will work similarly, then wash in water using a different foam brush over the surface using several water changes. Brushing the surface while washing or toning will greatly improve the effects, much like watshing anything with a sponge using friction is better than soaking only.

OP since you are very experienced with cyanotypes (I prefer the term blue print since they are not cyan) I don't suggest cheap watercolor paper for you, but you should certainly use fresh sensitizer chemestry, but am sure you know that already. My experience is that ferric ammonium citrate solution (20%) will keep for only a few months. It is a mineral supplment, a food, that bacteria and fungi just love. A drop of dish detergent may substitute for the tween.

Alan Townsend

[diagonale-du-flou]

Thanks so much!

BTW- do you (or anyone on thread) recommend a good online source for Tween?

thanks again!

You can find it online as a cosmetic supply under the name polysorbate20, generally in the form of a dissolving powder

I had the same kind of problem with cyanotype HPR, which I solved by moistening the paper and adding a few drops of tween to the solution.

[agregov]

I don't think this is a paper problem. It's likely a chemistry issue. I highly recommend Christina Anderson's Cyanotype: The Blueprint in Contemporary Practice. She has lots of problem solving tips included.

[Tin Can]

Welcome ALT!

For too long estranged!

[malexand]

Thanks so much!

BTW- do you (or anyone on thread) recommend a good online source for Tween?

thanks again!

Amazon - search 'polysorbate tween'

[Pete Oakley]

For anybody in the UK reading this Tween 20 is readily available from Amazon. Just type in Polysorbate Tween and there it is. I've just ordered some.
Pete.