Cleaning Photographic Trays and Other Chemical Vessels: ======================================================= by Jerry Finzi Bottles and trays used in photographic processing and developing are usually just rinsed with water, but when they are stained they can be brought back to "almost new" condition by using a strong solution of hydrochloric acid. The mix should be 1 part hydrochloric acid to 3-4 parts of water. This solution removes the lime deposited from hard water. It is this deposit of hard water that holds all of the chemical dicoloration, so when it is removed, the other impurities will be washed away along with it. Caution! With the previous solution, be careful not to get any on the fingers or hands, and rinse your trays to ensure that all of the acid is removed. Developer and fixer vessels often aquire a blackish stain of metallic silver which can be removed with nitric acid. Developer stains can also be removed by a solution of potassium permanganate or bichromate and sulphuric acid (the same as used in reversal processing). The brown stain would then be removed with a 5-10% solution of potassium metabisulphite. Most stains can be removed by the previous methods but if there are deep stains that have penetrated on porcelain trays, it could very well be that the porcelain finish was faulty to begin with. The best remedy in these cases is to replace the trays with better quality porcelain. If you have stainless steel tanks or trays, don't think that they are truely "stainless" when using photographic chemicals. Rust, grime, and hypo deposits will build up on stainless steel if constant rinsing and cleaning is not done often. Using a stainless steel cleanser like Bon Ami or another cleanser made specifically for stainless will bring back the shine of this metal. Cleasners like Ajax should not beused on stainless steel as they are too abrasive. Bottles are so cheap nowadays (plastic or glass) that it would make sense to simply replace the old ones when stains get out of hand. To prevent difficult staining on any type of bottle, tank or tray, get into the habit of rinsing each vessel completely after use and drying them. This will prevent any difficult stains from building up. Remember to use warm or hot water when cleaning the newer "accordian" type of plastic containers (like Falcon) as this will dissolve any chemicals that are stuck in the pleats of the bottle sides. Just be careful NOT to inhale any vapors caused by the hot water and chemicals. ======================================================================== (c) Copyright, 1989, Jerry Finzi All right reserved Finzi Studio 36 west 20th Street NYC, NY 10011 212-255-2110