Has been years since I needed to use my MacBeth TD-504 transmission densitometer. Unfortunately misplaced my notes on using the densitometer. I am using it to read B&W negative densities. On the front of the densitometer is a circular rotatable knob that clicks into 4 positions. There is a colored dot for each position: red, yellow, blue, and green. Question is which position should the round knob be in for reading B&W negative densities and is the colored dot to be read at the 12:00 or 6:00 position?
thanks
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