[julianburke]

All tube cameras needed to reach stability before showtime. To minimize this time they were left 'on", that is the all filaments were kept on 24/7 with no plate voltage when not in use. All tube cameras required some tweaking before showtime.

Yes, all early cameras required considerable light to make them work properly but as time went on they were able to develop tubes that required less light. The English were making far better tubes than RCA or GE. In England EEV, (English Electric Valve Co.) were making high quality tubes but were also more expensive, but most studios bought domestically so EEV's are scarce in this country.

For a TK41 camera, 2P23's were developed and tested/marked specifically for it's best specific color spectrum. Usually each tube had a suffix letter (R/G/B) for its' tested color spectrum. Fortunately red was an easier color to match for as it is probably the most important color in the three as in making good flesh tones. Testing tubes for their efficiency in the RGB spectrum's will make the camera more efficient and thus use less light. These tubes are complicated to make in manufacturing and no two are ever exactly alike so they are sorted out for their best application.

Early studios who did use lots of light had to take this into consideration because artists/performers who had to wear heavy costumes could pass out due to heat exhaustion and their makeup would also run and have to be done over and over many times. All television actors who worked in the '50's will tell in their memoirs about this problem. Also A/C wasn't everywhere either.