Archived posting to the Leica Users Group, 1999/08/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]George Huczek wrote: > > At 01:15 PM 17/08/99 -0700, you wrote: > >Roy Feldman wrote: > >> > >> I realize there are commercially available products but--- Does anyone have > >> a home brew for cleaning plastic developing trays? > > > >For years I marked my trays. Now I don't. The best thing to clean a developer > >tray is fix. > > Use a concentrated potassium permanganate solution. It is a strong > oxidizer. Let it stand in the tray for several hours. You can also add > concentrated sulfuric acid to it for greater efficacy. Remove, then repeat > using sodium metabisulfite or sodium bisulfite solutions. It chemically > acts to take care of the permanganate stain. Works well. I've used it. > The permanganate/sulfuric acid mixtures are common reversal bleaches. > Another home brew cleaner can be made using a mixture of sodium > dichromate, sodium sulfate, sulfuric acid and sulfamic acid, if you happen > to have the chemicals available. These are essentially the ingredients > used in Edwal's tank and tray cleaner. The sulfamic acid may be the one > chemical not normally found in the darkroom, so the permanganate stain > remover indicated above will likely be the best bet for those who have > access to the chemicals. > Excellent powerful stuff that should be used with mouth/nose and eye protection and washed down the drain with a lot of water. Too rich for my blood! I would love to have Pyrex Glass trays! Mark Rabiner