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Old March 6th 10, 10:36 AM posted to rec.photo.darkroom
Claudio Bonavolta
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Posts: 50
Default Color & B&W Densitometers

Nicholas O. Lindan wrote:
Some enlarging meters are also very good B&W densitometers:

http://www.darkroomautomation.com/em.htm

If you are enlarging the negatives then the proper place to
read the density is at the enlarger's easel. It gives you
the effective density in your equipment - taking into account
flare and calier effects.

If you are doing zone system calibration then what you want
is the EI and development time that gives perfect prints on
#2 paper in your enlarger, not some arbitrary set of densities.

You also need to find the total exposure to the paper
that results in almost not white and almost but not quite
totally black. The difference in exposure in stops between
these points is equal to the difference in negative density
you want for spanning Zone I to Zone IX.

--
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121



Absolutely, any enlarger timer that gives an exposure time can be used
as a densitometer or to measure negative contrast too, an example with
my free softwa
http://www.bonavolta.ch/hobby/en/photo/darktools.htm
Which will be enough for the majority of printers, at least with silver
gelatin.

Said that, the use is not exactly the same and some densitometers offer
features that are generally not available in enlarger meters, like
reflection or UV densities measurement which are useful in other processes.

Claudio Bonavolta
http://www.bonavolta.ch

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