I am very much interested in this subject. If it's not possible to calibrate an old worn out meter, it's still possible to check the performance of the meter. I am not sure as to which color temperature to use. Kyoritsu Electric Co. Ltd made a good number for standard light source as well as meter and shutter testers. Many of them have color temperature of 2800K although a number of newer LED based ones specified as only white LED and I don't know the color temperature. Since most film are daylight balance film it makes sense for the light source to be daylight equivalent but then I am not so sure about this. Anyone has any idea about this?
Originally Posted by xo-whiplock
Using a dimmer changes the color temperature as you dim it down so it's not a good thing here.
What I did in the past is to use a dichroic color head. I used a Beseler 45 computerized color head which has accurate filter display. I turn all the filter off and then check the brightness at the diffuser which is a 6'' circle with a spot meter. It's about EV15 in this condition (I have to dial in equal amount of filters a bit to get it exactly EV15). Checking eveness of the brightness with the spot meter and found within 1/10 stop so it's ok there. Dial in equal amount of filtration of C, M, Y and checking the brightness with the spot meter I get to about EV9 with all the filter dialed in.