Tom Ferguson (tomf2468@pipeline.com)
Tue, 26 Oct 1999 12:55:06 -0700
All of the following is my opinion, and supplied as an option.
If you are either enough of a "control freak" that you just have
to have to own a densitometer, or are truly doing the research
that requires that level of precision: just ignore me ;-)
Very few photographers need a densitometer. For most it either
collects dust (an expensive dust collector) or becomes a
habit/obsession that just burns up time (time you could be
shooting and printing).
There are two good alternatives to a densitometer: the "two hole"
trick and the "spotmeter/closeup filter" trick. Both require you
to buy a step wedge (step tablet). Kodak's (last I looked) had
gotten way too expensive. Stoufers (219-234-5023) makes nice
ones. I use their 1/3 stop version (T3110). The "uncalibrated"
version is more than good enough for general use.
"Two Holes" trick: I think I learned this from our own "Judy".
I'm not very accurate with it, but far more than 1/2 my students
do great with it. Take two 3.5x5 recipe cards. Punch a small
hole (hole punch, nice and clean) in the middle of both cards.
Lay your negative and your step wedge on a good (even) light
table. Place the hole of one card over the spot on the neg you
want to measure. With the other card, placed over the step wedge
(which is also on the light table), match the "tone" of the neg
to a step on the wedge. My problem is that the neg is usually a
mixed (continuous) tone, and the wedge is pure tone. Confuses
me. But, as I said, most students love it and do very well with
it.
"Spotmeter/closeup filter" trick: This is a simplified version of
Phil Davis / Beyond the Zone System. You can buy (usually a
special order) from Tiffen a set of three "closeup filters" (plus
diopters I believe) that will fit most spot meters. Place all 3
filters on your spotmeter and it will only focus at a very close
range. Place your neg and stepwedge on a light source. Measure
the neg (move the meter/filters in and out until you've achieved
focus), find the step that matches. With a bit of wiring, you
can set up a dimmer and calibrate, allowing you to measure
directly (without referring to the stepwedge each time).
Remember to aim the meter directly at (and parallel to) your neg
and/or wedge.
Both of these options will work quick and cheap (you probably own
most of the stuff). Most photographers use them to set
development times (not done often unless you constantly are
changing film brands) and to determine the "first try" contrast
and exposure on an alt print. That is about it.
-- Tom Ferguson tomf2468@pipeline.com http://www.thefstop.com/tf.html---------- >From: LukaCA@aol.com >To: alt-photo-process-l@sask.usask.ca >Subject: Densitomiters >Date: Tue, Oct 26, 1999, 11:06 AM >
> I need to purchase a densitomiter for calibration of my Pt/Pd > printing. > The problem I am having is most of the machines(Heiland,Mantis) that I > see > advertised have very short throats. My format of choice is 12x20, and > with > only about four inches of reach, I will not be able to read a large > portion > of the neg. Does anyone know of a densitomiter that will work for this > and > other "big" negs? Or is there a way to modify smaller machines to > increase > their throat length?
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