I am using Tetenal's C41 (1 Liter) kit for my first time developing colour neg film in a standard developing tank and have a few questions. The instructions say to mix up the full liter and develop as follows: First 1 to 4 films for 3 minutes 15 seconds Next 5 to 8 films for 3 and half minutes Next 9 to 12 films for 3 minutes 45 seconds Next 13 to 16 films for 4 minutes I presume this means I can develop up to four films together and re-use the developer another three times? But if I only develop 1 or 2 films each time, will I still only get four development runs out of the kit and therefor not get as much value? Is it ok for example to only mix up half the kit if only doing two rolls at a time? This way I could increase the capacity and still get sixteen rolls in total. What agitation is required?