[net.rec.photo] densitometer alternative

anand@utastro.UUCP (Anand Sivaramakrishnan) (07/16/84)

I was thinking that if you use a large format camera with a
spot meter you already have a transmission densitometer...

I've never worried about numerical values of the densities of the
zones, as my zones are by eye on a 'test' print with the unexposed
neg. at 'print black'.

But if one exposes a 4x5 neg such that it is divided into two 
(or four) zones, all one needs to do is put the neg on a light
table (think about the spectrum of the table and the response
of the meter, though) and one has a transmission densitometer
(after judicious application of logarithms, exponents and their
ilk).

I'm sure a roll of 120 film will also be amenable to this
method... in fact it will be more convenient, as you can
have one roll with the ten zones, one on each square.