[pure-silver] Re: Iodide in emulsions...

  • From: Ray Rogers <earthsoda@xxxxxxxxx>
  • To: pure-silver@xxxxxxxxxxxxx
  • Date: Sat, 28 Nov 2009 06:39:07 -0800 (PST)

 
The thing that troubles me is how your graphs sort of imply the different components have different maximum densities... I doubt it is as intense as portrayed, even that they are just schematic.
 
There are quite a few different approaches to variable contrast, so everybody can be correct. Fuji even makes GRADED variable contrast papers, a cool redundant use of the technology.
 
Ray
 
 
---------------------------------------------------------------
--- On Sat, 11/28/09, Ralph W. Lambrecht <info@xxxxxxxxxxxxxxxx> wrote:

From: Ralph W. Lambrecht <info@xxxxxxxxxxxxxxxx>
Subject: [pure-silver] Re: Iodide in emulsions...
To: pure-silver@xxxxxxxxxxxxx
Date: Saturday, November 28, 2009, 12:42 PM

From my 10-year-old conversations with Ilford, modern VC papers have three emulsion, which are of different contrast and different threshold sensitivities. In addition, they react quite differently to blue or green light. See attached images.











Regards




Ralph W. Lambrecht


http://www.darkroomagic.com








On Nov 28, 2009, at 05:57, Richard Knoppow wrote:

My understanding is that the emulsions of variable contrast paper are all the same contrast but have different threshold sensitivities. I have yet to find a really clear explanation. Some early VC papers seem to have been combinations of a high and a low contast emulsion.


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