Quote:
Originally Posted by Telecolor 3007
Man, I didn't thought they where so hot. Probably the needed special lamps.
But why some where blue?
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As MIPS said, for white balance. If you look at the description, it tells the color temperature of over 5000K.
Also, the reason they were so hot and high wattage is because they were run at high temperature to get the less orange color (3200K) than home lighting (2700K) without a blue filter, and put out lots of light for the films that were not very sensitive by modern standards. The blue bulbs reduced the light output, but made the color balanced for daylight color film (nominally 5400K). The alternative would be to use the plain bulbs and put a blue filter on the camera lens.
The penalty for this high temperature was that the life was greatly shortened to maybe 10 hours instead of normal house light bulb life of 1000 hours.
I used some of the plain ones (not blue) for black and white photography when I was in high school (about 1960).
TV studios, both black and white and color, used high temperature incandescent bulbs for a long time, but they always put them on dimmers and set them to 70% of nominal voltage. This both increased the life and gave the lighting director some adjustment range upward in brightness as well as downward. Use of incandescent bulbs meant that studios needed huge air cooling capacity. These costs have been cut greatly by the use of first, fluorescent lamps, and more recently, LED lamps.