calibration of 361T Transmission Densitometer

[mitch brown]

hi
does this densitometer need to be calibrated to read neg densities or can you just zero it and then measure the negs. i would like to read pyro negs for a film speed test.
thanks
mitch

 

[Don12x20]

When I bought my used 361T, I presumed I could just zero and read.
It did read, but way off compared to my other densitometes (for optical; I had no reference to compare on the UV spectra).

I bought the reference step table and ran the calibration (you can get manual off the website).

now the readings for standard B&W film (not pyro) match the other denistometers, and the pyro negative readings changed substantially from the first reading.

So, the answer is....it depends. My experience indicates you ought to recalibrate.