After coating Kallitype and Platinum...

[Fred L]

Can the coated paper be kept in a light tight box or paper safe, or will it be need to be exposed same day ? Coated more than I should have recently and had a long day because I thought I had to expose it or lose it. If I can hold onto it, how long before I need to give it some UV love ?

Similar, after exposure, does the paper need to be processed asap or can it sit in a paper safe for a few days/weeks ?


tia,
freddy

[martiansea]

I've found that kallitypes can sit for awhile, but I haven't done that with platinum. Long ago, they sold ready-made platinum paper, so I'm assuming it's possible with at least some formulas.
I've let VanDyke brown coated papers sit for months in a paper safe and they still printed, though I can't tell you if it was as good quality as it would have been fresh.

But here's my big caveat regarding storing kallitype, or similar, papers in a paper safe for any period of time: I would advise against leaving a stack of papers in there all on top of each other. I've found strange artifacts in the prints with portions of the papers having noticeably less density/contrast than other parts, and the demarcation between dense/less dense was always exactly the squared off shape of where another paper had been sitting on it. There is some kind of interaction happening when the papers are touching each other. This has happened both in a paper safe and in a dark bag. I've been wanting to do some experiments to try to determine exactly what is happening. I don't know if it's some kind of out-gassing, or maybe even subtle differences in humidity from moisture being trapped between the papers. Still an open question at this point.

If you do decide to keep a stack of coated papers in a safe, be sure that they are neatly layered on top of each other, so that if there is any change in characteristics, at least it will happen evenly across the entire paper. Maybe interleave glassine or similar between them so they aren't physically touching? Maybe sealing each one up in an archival storage bag would keep them better? These are things on my list to try.

[Alan9940]

In the past, I have stored coated paper for pt/pd prints for several days but in recent years I don't because I've found I get better dMax by humidifying the paper, coating it, letting it dry just enough that it won't stick to the negative, then exposing and processing. My theory is that the emulsion sinks too far into the paper, if it's left to sit for days, and weakens the blacks. Don't know this for fact because I've never measured it with a reflection densitometer. Never done kallitypes, but after watching Andrew's videos I'm thinking about venturing down the ULF rabbit hole building my own camera and using x-ray film to start.

[Fred L]

thanks for the info everyone.

guess I might have to coat some small test papers, let them sit, and compare to fresh coated papers. the idea of the solution migrating deeper is an interesting one. I may have to call Dana at Bostick and see what he thinks about storage.

kinda OT, but glad to see things are back in stock at Bostick and Sullivan.

[martiansea]

I also heartily recommend Artcraft Chemicals for everything to make these kind of prints. Excellent prices and service.

[Fred L]

Thanks Martiansea, have heard good things about Artcraft.

I like Bostick because they sell kits (woohoo) but also because they have lots of information on the different processes, and the prices are online, which makes it easy to plan/budget.

We're fortunate to have such retailers for these niche processes.

[esearing]

I was playing with Salt and Moersh's Lobotype (similar to Kalitype) and found I could keep them in a light tight box for up to a week. After that they seemed to be gaining a bit of oxidation and discoloration. Like mentioned above coat then use provides best contrast. I would coat paper in the morning and expose/process in the afternoon.

[bob carnie]

Can the coated paper be kept in a light tight box or paper safe, or will it be need to be exposed same day ? Coated more than I should have recently and had a long day because I thought I had to expose it or lose it. If I can hold onto it, how long before I need to give it some UV love ?

Similar, after exposure, does the paper need to be processed asap or can it sit in a paper safe for a few days/weeks ?


tia,
freddy

Hi Fred

If you keep the paper in the same humidity lets say 50% at all times then the chemistry will stay on top of the paper where you want it to be, if when storing overnight the humidity drops then you risk
the problem of the coating to sink deeper into the print which will indeed give you problems . I think overnight storage in a dark room with good humidity is possible but frankly I would not do it . unless of course you coat
and get an attack of kidney stones, then just leave the paper and head for the nearest emergency, after the Morphine kicks in you will not care about the paper.

I coat each morning first thing, give about 1/2 hour to dry and then expose for all my work.

regards

Bob

[Fred L]

haha, thanks Bob the humidity thing would be a pita to maintain.

Consensus seems to be coat and expose same day (which is what I've been doing). Won't make the mistake of coating too many sheets next time lol

[domaz]

If you want an alt process where you can do all the up front work and then just take it out of the freezer to expose, look into Carbon Printing. I have made carbon tissue and sensitized with Dichromate and frozen them immediately after drying and they last for at least a week that way. If you use DAS (an alternate less toxic sensitizer) you don't even need a freezer and the resulting tissues will last basically forever, ready to be exposed at any time.