Eyeball densitometry

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erobkin@uwc.edu
Date: 05/17/00-04:00:42 PM Z


In fact Kodak sells (or used to sell) a printed density step card with holes
punched in the middle of each step. The eye is even more sensitive to
seeing if the tone showing through the hole matches the tone around the
hole. I believe these were intended for use with prints or with printed
ink.

DIY project maybe? Cottage industry for someone on the alt list? How do
you calibrate a DIY one without access to a "real" densitometer? I have
something like this I picked up somewhere that was intended to help in
calibrating color prints. I'd go look for it but that is tilting at
windmills. I'll have to wait until the natural convection of the debris
brings it to the top of its pile.

ER

-----Original Message-----
From: Judy Seigel [mailto:jseigel@panix.com]
Sent: Wednesday, May 17, 2000 4:15 PM
To: alt-photo-process-l@skyway.usask.ca
Cc: Alt Photo
Subject: Re: Still learning Pt/Pd

On Tue, 16 May 2000, Nick Makris wrote:

> Judy and Eric,
>
> I also have recently printed a 21 step negative which didn't provide any
> enlightenment - it printed just fine. Once again, I have no densitometry
so
> I am unable to compare the steps to the areas in question.

Nick, that's what you do with the white cards: punch holes with an office
punch in two white cards. Put one hole over the area you want to "match"
in the step tablet, then run other hole over the print until it matches
(or vice versa). The human eye is SURPRISINGLY sensitive in this kind of
matching -- in fact early densitometers relied on operator matching tones
by eye.

Judy


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