Re: DR vs. f-stops

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From: Sandy King (sanking@clemson.edu)
Date: 09/10/03-12:01:59 PM Z


I am assuming you mean nine stops, and not nine steps of a 21 step
transmission step wedge, because each of the steps of the wedge is
log 0.15, or 1/2 stop.

If the measured value is really nine stops the actual negative
density range would be slightly less than 2.7 if you graphed it and
made a curve because some of the density would consist of toe and
shoulder. But your calculation is generally on target, 9 stops X log
0.30 = 2.7.

You will recognize that a DR of 2.7 is extremely high. It would
probably work well with salted paper and VDB, and maybe albumen, but
not with any of the other processes we normally discuss on list.

Sandy

>Also, if I have a neg with an range of 9 stops, using the ratio
>below, does that mean the DR of the neg is 2.7????
>
>thanks again,
>n
>
>----- Original Message -----
>From: <mailto:jkschreiber@earthlink.net>Keith Schreiber
>To:
><mailto:alt-photo-process-l@skyway.usask.ca>alt-photo-process-l@skyway.usask.ca
>Sent: Wednesday, September 10, 2003 10:11 AM
>Subject: Re: DR vs. f-stops
>
>Do you mean something like: 1 stop = 0.3 density units ?
>
>Keith
>
>----- Original Message -----
>From: <mailto:nick@mcn.org>Nick Makris
>To:
><mailto:alt-photo-process-l@sask.usask.ca>alt-photo-process-l@sask.usask.ca
>Sent: Wednesday, September 10, 2003 8:45 AM
>Subject: DR vs. f-stops
>
>Dear Sensotomitrists(sic),
>
>For those of you really into the technical side of all this, you
>probably have the answer(s) to these questions.
>
>Is there a linear association between f-stops and dynamic range?
>
>Regardless of whether it's linear or not, what is the association?
>
>
>Many thanks,
>
>Nick
>
>


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