Processing tank comes in plastic, full steel and steel with plastic cap.

Plastic type has different design and individual reel. It is easy to clean and internal heat can be kept for a longer time. Some design allows thermometer to insert at center to measure at time of processing. Plastic reel can be adjusted to fit 135 and 120. The bad side is that it is bulky, consumes more chemicals, inverted agitation is not easy and cannot use water bath to maintain constant temperature.

Steel type is rather simular to one another and steel reels can be accessed to all. Its size is exact and requires less chemical. Inverted agitation is handy. With water bath method, it is easy to keep constant temperature. The bad side is it must be cleaned thoroughly otherwise rusting will occur. In windy and cold situation without controlled water bath, the temperature will change rapidly. Steel tank with plastic cap is the worst design.

Steel tank (with steel cap) is the best choice. It is because high speed and infra-red B/W film is so sensitive that only steel tank can be used.

Cap of tank is a two layers design to lock out light and allow water to flow in and out. Steel cap has been coated with dull black color to avoid reflection. Therefore we must check it before use and clean it well afterward.

PROCESSING TANK