When we do bleaching of cyanotypes with an alkali, the highlights start disappearing quite rapidly while the shadows lag behind significantly
The same time one would not want a KCN solution at such an outdoor event.
I've been doing wet plate almost weekly for the past three years. I have some thoughts. I've been using ammonium thiosulfate 1:3 for the past two of the three years. It seems to work well and is fairly quick. I'd like to try some KCN but for reasons no one has mentioned. It's far more water soluble than ammonium thiosulfate or "hypo." Most of the time this isn't an issue for me as I give my plates a quick rinse, keep them wet, and take them home for a complete rinsing. Ammonium thiosulfate is a bit stubborn to get out of the emulsion and like any fixer you can't just leave some of it. KCN being very soluble takes far less water to completely rinse out and that's a HUGE issue when I'm shooting at an event one plate after another. With am-thio I have to put the completed tins into a holding tank, take them home to rinse and dry. With KCN I could rinse them well enough there, dry, and varnish. The photos could be ready for take home in an hour or so. If you're working in a studio this isn't so much an issue but if out on location it becomes a big headache. I have yet to be at a location where I had running water available or even large quantities for washing a dozen or two plates.
Kent in SD
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That seems like a practical benefit of using KCN - however, if you look at the solubility of the 2 fixers, that of ammonium thiosulfate is actually higher (by nearly 2.5X) than KCN. So the solubility is not probably reason for KCN being more effectively washed out of the collodion. I wonder if the phenomenon that occurs in the traditional silver gelatin, i.e. bonding of the thiosulfate ions to the gelatin and the cellulose of the paper which then takes much longer to clear out, is also behind here. Of course, this is more prominent in the case of sodium than the ammonium thiosulfate. The remedy in that case has been the use of hypoclear agent (basically sodium sulfite) which reduces the washing time significantly. It could be that thiosulfate in wet plate also attaches itself to the collodion (which is afterall nitro-cellulose.) Has there been any attempt at using hypoclear agent for wet plate?
:Niranjan.
I would not take the powder/pure form of course. Highly diluted as a fixer it should be no more dangerous than my silver nitrate or developer laden with acetic acid which can burn. Wondering if you do wet plate yourself and am familiar with it?
I prefer it as a fixer for tintypes and ambrotypes. I have other fixers and use them regularly, but prefer the KCN for certain applications. I have a jar left so I will have the ability to fix quite a few plates - just wanted a source for more for when the supply runs out. I do work at large industrial sites with in house labs and will try those as well.In America and developed democracies, I think you will not be able to get that..
This is the price of urbanization, environmental conditions, and so on.
Available in Egypt, my country sells by kilo.
But despite that, I didn't like to use KCN,, for bleaching. It's a relatively expensive ingredient (from my point of view).
Therefore, I was able to find very suitable and very affordable alternatives.
So, I advise you to tell us what you want to do with (KCN) >>>> Maybe we can suggest you a suitable alternative that you didn't think of.
I'd take any info you feel comfortable passing on.There's a chemical supply place down in Richmond, Virginia (whose name escapes me at the moment) who would sell wet-plate chemistry to folks looking to buy stuff in non-industrial quantities (I got my glacial acetic acid and some of the other nasties from them). For the nasty stuff you had to fill out an FBI form to validate you were not buying it for nasty purposes. I should still have some of the bottles down in my chemical store - I'll look up the name later today and post it here.
It's not cheap, but available. I don't know what hoops you need to jump through to order it, though.
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