Archived posting to the Leica Users Group, 2005/12/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I've had good luck using propylene glycol in place of some of the TEA and reducing some viscosity issues. My basement darkroom in my northern climate left me with solid PC-TEA in winter when I first started experimenting with it. Part of why I wanted to use a long-shelf life concentrate was for fitting in with my sporadic trips into the darkroom and knowing I had trustworthy chemical ready to go. With the fussing around to get my PC-TEA re-liquefied, it was losing part of its appeal for my application. Another plus of the PG is that ascorbic acid and phenidone go into suspension much easier with less heating and then I can top up with the TEA. The TEA based concoctions I've experimented with seem to end up with very different freeze points and PC-TEA is the only one that I've had problems with at the temperatures that my darkroom tends to settle to in the winter. Mike Durling wrote: > Maybe I better reiterate that it is the stock solution that has no > water. You dilute the stock with water at a 1:50 ratio. A little > goes a long way. The Triethanolamine forms an alkaline when mixed > with water. The secret of its longlevity is that nothing reacts with > it until you add the water. Photographically this means that you > don't need sulfite, which as you know, eats away at the grain and > sharpness. > > Now the viscosity is another thing altogether. When I got mine it was > solid, like a rock. I had to leave it in hot water for quite some > time to get it to melt. Once it was melted it seemed to say that way > in a moderately warm house. The stock solution is also a liquid. > Looks kinda like a thick rodinal or maybe maple syrup. > > Mike D >