Digital BW, The Print

Hi,

I have been doing something quite similar, but using an Epson V500
scanner.  Something that others might find useful is a great, and
free, image analysis program called ImageJ:

http://rsb.info.nih.gov/ij/

This was developed by researchers at the US National Institutes of
Health, and is widely used for scientific applications, such as
analyzing microscope images.  It can read 16-bit tiff files, among
others, and has built in tools for measuring pixel values and
dimensions in images.  It has two particular features that are of
value here:

1. It can measure the average pixel values of selected regions (a
rectangle for instance) and saves the results of multiple measurements
in a nice table that can be copied or exported to other applications,
like Excel.  It is very easy to move the rectangle from one step to
another and measure each with a single key click.

2. Images can be calibrated by fitting known values to a variety of
different functions.  Once the image is calibrated, the values
measured are read out directly in the calibrated units (e.g. density).
 If the image capture is reproducible, the calibration curve can be
saved and applied to subsequent images.  This seems to work well with
the Epson scanner, using VueScan to save "raw" files with defined
capture parameters.  It probably wouldn't work with camera images,
unless you went to extreme measures to control the lighting, etc.

I have been using a scanner and ImageJ for measuring both negative and
print densities, and it makes everything very easy.

I hope others find this useful.

David