Continuing to use Kodak Aerographic 2645, as I have been doing some comparative testing of twin-lens reflexes that use 127 film (yes, I know, why would you?) In due course I hope to have a comparative report here so you can decide which to buy. Meanwhile a note on developing. As well as the late Patrick Gainer's ascorbate developer, I am trying his PC-TEA formula. You can read all about it here. P=phenidone, C=Vitamin C, TEA=triethanolamine. Thus PC-TEA. Now triethanolamine is an interesting liquid, because it is both an organic solvent and an alkali. That is to say, if you dissolve your developing agents (ascorbic acid=Vit-C and a pinch of Phenidone) in neat TEA (not tea!), they are not exposed to any water. The theory is that rather like rusting iron, for the developer to go off it needs to be in the presence of both air and water. So a stock solution of developing agents in TEA should have a very long shelf life. When you want to use it, 8ml of stock solution + 392ml of water makes 400ml of working developer, used 1-shot. The clever bit is that the TEA, having so far worked as the solvent, now becomes the alkali and activates the developers. The benefits are several - a very dilute working solution, so minimal environmental or health risks, long shelf life, cheap to make and use. And the actual performance is fine, with developing times similar to other brews. Vitamin C is safe to handle, TEA is a common ingredient of cosmetics (though it should not actually be drunk), and the phenidone content of the working solution is only 50 milligrams per litre. If there is a snag, it is that TEA is viscous at room temperature, so I find it best, when I make up a batch, to dose it into little screw-top tubes each containing 8ml (enough for 1 tank of working developer). While it is still hot, once you have dissolved the developing agents, it is easy to measure it into the tubes with a 10ml syringe. Here is a picture taken on Aerographic 2645, developed in PC-TEA. Camera - Yashica 44LM Update some months later:
Storage life is looking good so far. The PC-TEA concentrate is pale straw colour when first made. After about 5 months, in little individual sealed glass tubes (10ml tubes containing 8ml of concentrate), the liquid has darkened to near-black, but still works as normal!
1 Comment
|
ReflectedAn occasional and irregular blog, mostly of photographic experimentation and photographic history. Archives
April 2021
|
Copyright © 2023 by John Marriage