densitometers

Someone asked earlier for advice about densitometers.

Good names are X-Rite, Noritsu, Eseco, and Gretag/McBeth, but others
such as Tobias, Fuji, can also be quite good. There are really a lot
of bargains out there now on ebay since many of the services that
once used this type of equipment have shifted to digital.

I like X-Rite a lot because they have a good web site and supply
parts quickly from an on-line store. A reflection/transmission
densitometer such as the X-Rite 810 and some others in the 800 line
provide a lot of utility because you can use them to read both films
and papers and in either color or Visual Modes. There are also small
portable units that operate with batteries, though these are
generally available in either transmission or reflected but not both.
The X-Rite 400, 404 and 418 are examples. It is a plus if the unit
comes with calibration plaques and wedges because you will almost
certainly have to re-calibrate it.

You can generally get a good idea of the age of a densitometer by
looking at the display. Very old ones have analog displays, models
from the 70s and early 80s have simple digital displays, usually red,
and current generations ones generally have digital displays with
black characters.

Except with very new and expensive instruments it is generally not
cost effective to have defectives instruments repaired. Most of the
current generation X-Rite models have a self-pass test that is
activated when you turn the instrument on. This can be useful because
lots of densitometers are being sold by persons who don't have any
idea if they work or not and they offer them in "As is" condition.
Lots of people would not bid on an item offered in "As is" condition
but you can be reasonably sure that it will work if the seller
indicates that on power up it passes the self-past test with OK. Or
if they don't sell it you can ask about it.

Many people insist that you don't need a densitometer to make good
alternative prints, and that is of course true. However, a knowledge
of sensitometry is interesting and can greatly expand your knowledge
of how films and papers respond to exposure and development and can
save you a lot of time in testing.

Sandy King
Received on Sun Nov 23 22:40:13 2003