Does anyone know of a way to do a film speed and development time test with a scanner, a computer, and software like Adobe Shop?

-- David Sinai (dsinai@investran.com), February 12, 2002

Answers

Brilliant Question, David. You have your thinking cap on....

-- Fred De Van (fdv1@ix.netcom.com), February 13, 2002.

Not an original idea, though. Search through the previous threads. This has been covered several times before; both here and on photo.net.
It's ominous that no-one seems to have reported back on how it went.

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 13, 2002.

I'm one of those who brought up the possibility before.

I haven't tried yet. I'm thinking about easy, cheap and relatively accurate way to get calibration scales (density steps). I prefer it be mountable on 4x5 or 6cm carrer. Ideally, two separate steps, one 0.1, 0.2, 0.3, ... and another 0.05, 0.15, 0.25, ... or something like that. This is because I want to make sure a couple of technical issues are not in my way for the first time.

Any idea? Please let me know...

(It's probably not hard to find sources but I have been working on other things lately...)

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), February 13, 2002.

Lee filters stocks accurate ND acetates in densities of 0.15, 0.3, 0.6, 0.9, and 1.2D. My densitometer measurement of these has shown that they're within 5 or 10% of the stated density, even though they're only meant as lighting gels.
If you e-mail, phone, or write to Lee, they might send you a free sample swatch of their lighting filters. The swatch book contains 75 x 25 mm samples of all those ND filters, plus dozens more coloured filter and scrim samples. Each coloured filter comes with a transmission curve as well! What more could you want for free?
BTW Ryuji; a piece of clear acetate film has a density greater than 0.05D, you won't easily get steps that small, and anyway, that sort of accuracy is of little practical use in photography.

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 14, 2002.

Thanks for the info.

The reason I wanted such a strange pairs of density steps was because I wanted to make sure that the measurement system works to my expectation, not too much of practical requirement. Also, the density of the base itself doesn't concern me as long as it's small and uniform. My scanner gives me 16 bit data for each channel up to density of 3.5 or so. This leads to a statistical model estimation and verification problem. Once I get that part done, I can just use the model. You don't want to use the model that you don't know how good/bad it is.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), February 14, 2002.