Digital BW, The Print

Hi All -
I'm a little late to this discussion but perhaps can add a little to 
what Juraj has written.
Many years ago I was mixing Pyro formula from scratch but found that  
PMK worked at least as well,
and came partially pre-mixed.  I used it for all my fine art negatives 
- 4X5, but mostly 120 and
35mm.  I love the staining of the shadow areas, which allows for much 
better control of the highlights
without burning out shadows. Additionally, there's something in the 
formula that slows the silver particles
from migrating into adjacent areas with less density.  I don't remember 
the technical explanation, but the
net result is sharper delineation.  Depending on the subject and the 
light, there can be a dramatic
improvement in prints.

So 5 or 6 years ago, I started scanning some of those negatives, and 
the results were terrific. Because the
stain is greenish. brownish, yellowish :-), my best results have been 
scanning in RGB and as Jurj has mentioned, converting
to grayscale via channel mixing in Photo Shop. My logic for this is 
that the green channel controls much of
the shadow detail you want to show through (since most of the stain is 
in shadow areas).  Also, one
would have to scan the negative as if it were a transparency - i.e.: 
the scan comes up as a negative.
Only after working on it in channel mixer should it be inverted to 
positive. That will take some experimenting
because it's so difficult to make tonal judgments looking at a negative 
image, but IMO it's worth the trouble.

As far as grain is concerned - I think there may be a little more grain 
with PMK developers, but personally, I like
grain most of the time and never thought of it as a problem.

On Mar 28, 2006, at 4:40 PM, 
DigitalBlackandWhiteThePrint@yahoogroups.com wrote:

>
> Message: 2
>    Date: Tue, 28 Mar 2006 16:34:56 -0000
>    From: "jurajlipscher" <juraj@...>
> Subject: Re: Scanning Pyro Negs?
>
> Hi Jules & Martin
>
> 1. There is a fairly extensive article on scanning pyro negatives and
> selectively using different color channels in the magazine 'Ag' No.
> 26. Here is their webpage with the possibility to order back numbers:
> http://www.ag-photo.co.uk/
>
> 2. I have been working with PMK for the last 15 years and am presently
> also using Pyrocat HD. I scan both kinds of negatives either with
> EPSON 4990/Vue Scan or IMACON 646 and have beautiful results with both
> developers and both scanners.
>
> On and off I am poring over the following question which is directly
> pertinent to this list:
>
> Enlarging pyro negs (PMK and/or Pyrocat) on multigrade silver paper
> gives you the advantage of the yellow/brown stain selectively holding
> back the hard blue light of the enlarger so that the highlights be
> selectively filtered down by the stain and thus giving better
> differentiation in the highlights. This has been described in depth by
>  Gordon Hutchings (inventor of PMK) and also by Sandy King (inventor
> of Pyrocat).
>
> Now what I would like to work out is how to achieve similiar increase
> of differentiation of highlights in scanned pyro negatives. This would
> have to entail scanning the pyro negs in colour and then simulating
> the selective filtering by intelligent use of the channel mixer or
> some such in Photoshop.
>
> Has anyone any ideas in this direction or does anyone know someone
> with such ideas? ;-)
>
> best regards
> Juraj