Rotlicht
Hello everyone,
Unfortunately, no one has been able to tell me anything about it so far, which is why I’ve signed up here. So, first of all, a quick ‘hello’ to everyone, and straight away my first question:
Does anyone here know the ‘CMA Colormaster- ?P?? I was recently given one as a gift. It’s an exposure meter with a measuring ‘probe’ or ‘cell’ attached to a long cable. When you hold the cell up to the image, it happily measures away, but I can’t make much sense of the mostly two-digit values (0–100?!). Apparently, it’s the calculated exposure time… You can apparently also switch the device from one display (exposure time for b/w?) to three additional ones (one display per colour). The classic colour exposure meter?
In short: are you familiar with this device, and if so, do you perhaps even have a manual? Or do you have any idea what the measured values represent and how to use them (calibrate, etc., if necessary)?
Best regards
RL
TR
Hi RL. You’re right, it’s at least a basic light meter function, I suppose:
You place the probe on a part of the negative that is transparent with little detail – in other words, the shadows, the darkest areas of the resulting positive. Then you turn the exposure dial until the green (or central) LED lights up.
Before doing so, however, you must calibrate the device to your paper once. This is done by using the classic test strip method to determine the correct exposure time for the subject on the relevant paper. Now nothing else on the enlarger must be changed. Place the measuring probe on the relevant spot, set the (previously determined) time value on the dial, and calibrate the device by turning a second, small potentiometer (which must be located somewhere) until the green LED lights up. This must be done for each type of paper, as they have different speeds.
However, measurements taken with such a device should only serve as a rough guide for the first test strip. The darkroom light must be switched off during measurement.
