Re: Step Wedge

From: Gregory Blank ^lt;[email protected]>
Date: 11/11/04-04:23:48 PM Z
Message-id: <>

Your correct,...but.......

   Actually if thats the degree of accuracy you require, no
home darkroom test is going to cut it. One requires a sensitometer.
Controlled exposure duration and a host of temperature, agitation
and process monitoring thats quite frankly beyond most of the
applied users in this group. No slur intended.

   I tried while I worked for Omega to set up a very controlled
test procedure that allow me repeatable results, I was constantly
trying to Up grade what I was grudgingly given,....and was vastly
by lack of time, and resources for doing the job right.

On Nov 11, 2004, at 3:36 PM, Sandy King wrote:

> Etienne wrote:
>> As an abstract exercise (especially for someone who, like me,
>> occasionally
>> whips up his or her own negative emulsion for fun), it's interesting
>> to
>> know what the film does, on its own. But when I load my holders, I'm
>> after
>> the most direct understanding of what my negatives are going to look
>> like
>> when they come out of the Jobo, and rolling all of the relevant
>> practical
>> factors into the material characterization gives me this.
> But my point is not that practical testing in the camera is not
> relevant, but simply that it is invalid as a means of comparing EFS of
> different films. For that you need a system with a common light
> source and some control that permits repeatable exposures to an
> accuracy of about 1/10 of a stop.
> Sandy
Received on Thu Nov 11 20:49:07 2004

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