1945 Kodak Films handbook shows Wratten Process Pan as Weston 20 or GE 32, but this is from metering white subject. So the film is really four stops slower than that! However, it's a high-contrast film, thus "process" in the name. Developers are D-11 for 5 minutes. For "high" contrast, D-8 (2:1) for 2 minutes! (D-11 and D-8 are high-contrast developers that make D-19 look like a wimp.)