[filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE!

["Clark Guy" <guy.clark@sbt.siemens.com>]

HI, Constantine!

You are correct that if one adds uncontrolled  light scattering into the mix
of variables, one can obtain less reliablie results than if one eliminates
it.

I (for the purposes of discussion) chose to ignore scattering.   In my tests
at my old employers' labs, we used high quality  glass filters, and later,
when verifying the operation of our devices, we used high purity distilled
water (in highly polished quartz cuvettes)  with the appropriate dyes to
minimize the effects of scattering.

If a standard were created mandating the use of some particular type of
filter set for scanner testing, all of you would be using the same standard,
and your numbers would be comparable.

I still maintain that this can be done, and at miniscule cost to the
manufacturers of scanners. (compared to your advertising budgets, that is!)

Guy

-----Original Message-----
From: Kapetanakis, Constantine [mailto:KAPETAC@polaroid.com]
Sent: Thursday, August 08, 2002 1:49 PM
To: Clark Guy
Subject: [filmscanners] RE: IV ED dynamic range... DYNAMIC RANGE!


That is wrong.
The light scattering characteristics of different media are different. If i
am not mistaken that is called the "Q-factor".
Without elaborating much try this very simple experiment.
Take two different media of similar densities, as measured with a
densitometer i.e. a ccNeutral density filter and a gray scale target of
either film or another base material. Scan both with the same scanner while
disabling auto-exposure and you will get different results.

----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe 
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or 
body