Densitometers

[fw]

What should I look for in a densitometer for use with B&W film (pyro & non-pyro developed) in order to calibrate development? I know nothing about the terminolo gy of these things, and what features are essential, and what are not. Thanks

[William Marderness]

To read most black and white negatives, you need a B+W transmission densitometer, which is the least expensive kind, but not cheap. For a pyro developed negative, you need a color densitometer, which are very expensive. You need to take readings with the blue channel. I called X-rite to ask about using a blue filter with my B+W densitomter to simulate the blue channel. The technician told me that the readings may be inaccurate and the density of the filter may cause problems.