[pure-silver] Re: Reciprocity and Intermittency Effects in Enlarging Paper
- From: "tOM Trottier" <tom@xxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 07 May 2008 02:42:07 -0400
On Monday, May 05, 2008 at 10:03,
Nicholas O. Lindan <pure-silver@xxxxxxxxxxxxx>wrote:
...
> But, I am sorry to say, it isn't really relevant to
> the issues at hand - you are changing the image size.
> Over the 8-stop range under consideration this is
> equivalent to starting with a 2.5 x 3.75" print made
> at 1 second and comparing it to a 40 x 60" print made
> at 256 seconds. The two aren't going to be the same -
> and the reasons have nothing to do with reciprocity:
You forgot exposure changes due to lens extension, a significant
variable for large negatives and big changes.
...
> Again: Reciprocity failure has no practical effect in the
> darkroom over the normal range of printing times.
...
Or rather:
Reciprocity failure, if any, is one of a bunch of noise sources
which will affect final exposure when changing print size
significantly for an image.
The lesson: calculate for a first guess, then test.
tOM
-- Quidquid latine dictum sit altum viditur --
tOM Trottier +1 613 860-6633
http://Information.Architecture.Abacurial.com
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