Sandy,

How did you know which results were correct? I'm still having difficulty seeing why the step wedge density should not be measured in the mode that most closely represents the way in which the film is exposed - ie a measurement of the relative amounts of actinic light falling on the film.

If the step wedge measurements are being used to calibrate the UV measurements (which is unlikely to be as accurate as the standard densitomer calibration procedure), how does the software know what relative exposures the film received?

The question is: 'What is the purpose of the step wedge measurements - is it to tell the software what relative exposures the film had, or is it to calibrate the densitometer against the known UV transmission of a Stouffer step wedge?'

Can the software be used with other step wedges?

Best,
Helen