Developing the film (also done in semi-darkness like perforation) requires its own series of environmental conditions. The earliest method involves coiling the extensive 40-200 foot long films around wooden frames for handling. These racks were then dipped in a series of tanks and troughs containing solutions for soaking, developing, and washing. The optimal conditions for each step of the process and the developing solution can be found in the link to Carrier Corporation’s 1936 document FILM. Most processes call for temperatures between 73 and 75 degrees Fahrenheit with 65-70% relative humidity, and the solutions are typically 10 degrees cooler. The document also clarifies which Carrier products are best suited to achieve desired artificial climates.