
1) Photography equipment
Found on
https://www.crosswordclues.com/clue/developing-tank

A developing tank is a light-tight container used for developing film. A developing tank allows photographic film to be developed in a daylight environment. This is useful because most film is panchromatic and therefore can not be exposed to any light during processing. Depending upon the size and type, a developing tank can hold one to many roll ...
Found on
http://en.wikipedia.org/wiki/Developing_tank

(from the article `photography, technology of`) Amateurs usually process films in developing tanks. In this type of development roll or miniature film is wound around a reel with a spiral groove, ...
Found on
http://www.britannica.com/eb/a-z/d/38

A light tight container used for processing film, a darkroom's essential accessory. A light-tight container, made of plastic or steel, in which film is developed. The exposed film is loaded into the tank in complete darkness, and temperature controlled chemicals are added at precisely timed intervals to make the image and stable.
Found on
http://www.rodsmith.org.uk/photographic%20glossary/rods%20photographic%20gl

Small plastic or stainless steel tank into which 35mm or 120 rollfilm can placed in, on spiral reels, for processing. Lightproof tops allow solutions to be poured in and out in daylight.
Found on
http://www.silverlight.co.uk/resources/glossarynz.html

A light tight container used for processing film. (see Daylight tank)
Found on
https://www.encyclo.co.uk/local/20176
No exact match found.