Quote Originally Posted by JHannon
Hello All, I finally acquired a used densiometer (Tobias Model TBX). It seems to respond to changes in density but I would like to check it's linearity across it's range. Would a calibrated step gauge (Kodak, Stouffer) be the thing to get?

John.

Unless you plan to do very precision work the uncalibrated step wedges made by Stouffer and Kodak are entirely adequate for film testing, and much less expensive than the calibrated versions.

I am not familiar with the Tobias and can not help you with the spefic calibration of the unit. However, nearly all densitometers have a Zero feature which allows you to calibrate the unit back toi Zero by taking a reading with no film between the light and sensor.