Quote Originally Posted by xo-whiplock View Post
Okay... scrap the dimmer switch and projector bulb... I get what you are saying now with regard to "fixing" a camera's metering... can't do it if the photocell is worn out and lost its ability to produce liner output. So, if I am able to make a brightness box and my meter output falls outside of desired linearity, replace the bad parts with good ones. I guess we are back to the beginning of this thread, in that going outside and using daylight at different EV's is better then trying to mimic it in a box... without some specialized skills and parts. The old KISS principle. Thanks for helping me out.
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?

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.