HI All,

Just purchased a Macbeth T500 Densitometer from the bay... Light come on and it makes reading . I have a stouffer 4X5 21 step tablet. As a quick test I zeroed the instrument on #1 the clearest and then read number two. It's a non calibrated step wedge but it is assumed to in .15 increments. It turns out it reads more like .2... So what to do no instructions.. I plan on using for some film speed tests and alternative contact printing. Should I be calibrating just on the light source, do I need other something else? Any help would be greatly appreciated.

Thanks in advance