Macbeth densitometer help?

[jvuokko]

Hi,

I got Macbeth TR-944 densitometer. It is old (dated at 1984) but readings are very accurate.

But...

Although I got all stuff, including calibration strips and macbeths calibration "patchs". I am really helpless with this equipment. The manual (Operator's Manual) does not help much. It only tells how to use different modes like Density, Memory Bank, HD-LD, Offset Null Density...

So far I have only used it as Density mode and for transmission measurements.

And yes, I got good readings with it but there are something weird. When I take measurement, the displayed value is always relative change to previous value!

So if I want to get absolute density, I have to remove negative (or any other target) from the measurement area and take plain null reading. Then take the measurement.

This is frustrating, and as far as I understand from the Operators Manual, this really is not the proper way to use densitometer.

I am guessing that I have some button at wrong position or I have densitometer at wrong mode...

I will be very pleased of any help.

I put picture of densitometer and it's panel section as attachment.