Re: scanner density-value relation

From: Richard Knoppow <dickburk@ix.netcom.com>
Subject: Re: scanner density-value relation
Date: Wed, 09 Mar 2005 00:45:52 -0800

> For that matter reasonable measurements of density can be made
> visually by comparison to known neutral density filters.

You can put the negative exposed by a step tablet and the step tablet
on the unexposed blank area nearby the exposed area, together on a
light table and guestimate the average gradient by eyeballing. The
judgement error (in terms of psychophysical difference limen or just
noticeable difference) depends on the size of the patch and the
transmitted irradiance among various factors. But using a scanner is
preferable because experimental data are recorded in the form of raw
TIFF file which can be reanalyzed if the data is questioned later.

--
Ryuji Suzuki
"Well, believing is all right, just don't let the wrong people know
what it's all about." (Bob Dylan, Need a Woman, 1982)