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Please,is there anybody who knows, by the chemichal point of view,if aluminium t rays have some inconvenience for sheet film development ? I (and everybody) know that stainless steel, glass and plastic are the leaders for that purpose, but t he shelves of domestic goods presently have plenty of aluminium stuff which insp ire me using them in developing tasks. They are of several sizes, shapes and wit h little adaptations can be light proof. Thanks a lot.
Sergio, I'm not a chemist, but I had an aluminium cookset once and the one thing I'm sure of is that aluminium pits badly making it hard to clean. This could easily lead to cross contamination. If somethinmg like creamed corn or tomato soup can pit aluminum I'd hate to think what photo chemicals could do to it. I've noticed that the high end aluminium cooksets now come with some sort of nonstick coating or are hard anodized. I remember reading that citric acid will attack aluminum as will brandy and champagne(a french '75) so don't mix screwdrivers or french 75's in WW2 canteens!
I wonder if the aluminum will affect the chemestry? Also, in time, the acid base reactions of the process, plus the chemicals themselves may erode the trays. Film developing trays need to have grooves on the bottom so you can get under the sheet film during agitation. The film will stick to a flat bottom. Stainless steel is what's recommended if you want to use metal trays. Personally, I went from trays to HP Combi tanks in a "dip and dunk" procedure. Development is much more even.
Most (all?) developers are alkaline, and alkali attacks aluminium quite efficiently - put an aluminium item through a dishwasher sometime and see what happens.
Whether or not the aluminium dissolved into the developer will affect it's activity I do not know, but commercial developers contain chelating agents specifically to mop up small amounts of metal ions from tap water, so in general I don't suppose it would be a good thing.
If you want cheap water and light tight fittings, PVC pipes and other plumping items are available pretty well everywhere.
As already pointed out, aluminum is attacked by alkaline solutions, which includes all developers (except some Amidol-based formulae), rapid selenium toner, and a variety of washaids. It is also attacked by non-oxidizing acids, including weak acids like citric acid or acetic acid. So it is also not god as stop bath or fixer tray.
Aluminium is a definite NO-NO with photographic chemicals. Use plastic cat-litter trays, they're cheap enough.
What you can also use are the disposable paint tray liners at hardware stores. I think those are 50 cents or so.
But of course, the Peterson plastic trays are cheap and they never wear out. (at least I don't think they do)
Has anyone here ever worn out a plastic tray?
"Has anyone here ever worn out a plastic tray? - Yep!About half a dozen of them in fact. They all get little cracks and splits in the corners, and start to leak. The lightweight blow-moulded white plastic ones are a bit better, but they still don't last forever. Stainless dishes are the way to go for permanence, but the initial cost versus durability still makes plastic trays an attractive proposition.
Another problem with metal trays is rapid heat transfer. They'll transfer heat faster than planting your butt on a concrete park bench in January.
If the room temperature is significantly cooler or warmer than the processing temperature, a chemistry temperature shift in a metal tray may cause problems with developing times. Unless you plan to use your trays as frisbees, Cesco plastic trays are hard to beat. Patterson polyethylene trays are pretty durable also.I'm still using my old Ace hard rubber trays (remember them?) after 30 years of continual service.
Like any activity in life, purpose-designed tools are a lot nicer to work with than improvised tools.