Xref: utzoo rec.photo:1943 sci.electronics:2102
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From: beyer@houxs.UUCP (J.BEYER)
Newsgroups: rec.photo,sci.electronics
Subject: Re: Homebuilt transmission densitometer?
Summary: Try Uncalibrated wedge T21 from Kodak (I hope I got the number right).
Message-ID: <669@houxs.UUCP>
Date: 11 Feb 88 14:00:34 GMT
References: <2659@dcatla.UUCP> <11237@shemp.UCLA.EDU>
Distribution: na
Organization: AT&T Bell Laboratories, Holmdel
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When I bought a T21 scale, it was about $6. The steps are supposed to be
about 0.15 density units apart with the 'clear' patch at about 0.06 density
units (should these be called Driffields? :-) ). I measured mine with a
MacBeth TD901 densitometer and I feel the densities listed are close enough
for most work.

I'd worry about exposing film and hoping the densities come out as expected.
The reason I bought my densitometer is to find out if they are as expected.
After over 10 years, I finally get what I expect sometimes ;-).

You might try using  Neutral Density filters, but, unless you get them
somewhere much cheaper than my local dealer, a useful set would cost more
than a calibrated wedge.

The T21 is about 1/2 inch wide and 2-1/2 inch long.