[alt-photo] Re: New Platinum Prints

[ender100 at aol.com]

Etienne,


I print quite frequently with digital negatives and pure palladium—that has an exposure scale a couple stops above log  2.4 you mentioned.  Most people I know using digital negatives don't use short scale pt/pd.


Best Wishes,
Mark Nelson





-----Original Message-----
From: etienne garbaux <photographeur at nerdshack.com>
To: The alternative photographic processes mailing list <alt-photo-process-list at lists.altphotolist.org>
Sent: Sat, Apr 10, 2010 5:09 pm
Subject: [alt-photo] Re: New Platinum Prints


Davidh wrote: 
 
>This is something that's been concerning me lately. I've been 
>preparing my negs for palladium digitally using Mike Wares method. The 
>reason for this is that my printer (Epson 1400) won't allow me to use 
>any other method as the inks are not very dense. I manage to get 
>satisfactory gum prints but I'm thinking I could be missing out on 
>something in my palladium experiments. My exposure time using BL tubes 
>is 60 seconds. The prints look ok but nothing special. Could this lack 
>of negative density have something to do with the way they look? If so 
>why? 
 
Be aware that I'm not familiar with Mike Ware's method (although I have seen prints attributed to it) and I do not use digital negatives. 
 
There are two things at work here: (i) matching the negative density range ("DR") to the printing exposure scale ("ES"); and (ii) the character of the exposure scale, however long or short it is.  If the DR of your negs is too short to match the printing ES, you'll get low-contrast prints with murky (but not very deep) shadows and/or fogged-looking highlights.  But even if the negs have the right DR for the process, the characteristic curve of the printing process may be ugly. 
 
The standard long-scale Pt process has a very, very long linear scale with symmetrical, gently rounded toe and shoulder, typically printing the whole step wedge with some scale left over.  Therefore, you need to use negatives with a very high DR to obtain all of the available print zones with this process.  Photographers have not typically made negatives this "bulletproof" since the late 19th Century, so folks have tried a number of different methods to shorten the Pt exposure scale (adding dichromates, hydrogen peroxide, etc., etc.).  These tricks shorten the exposure scale by raising the threshold exposure -- not really a very promising way to go about it.  Anybody who has done serious sensitometry with the process has seen the ugly characteristic curves the short-scale versions of the Pt process produce.  I have yet to see prints made using any short-scale Pt process that came close to the look of "real" (long-scale) Pt prints.  Unfortunately, so many workers are using the short-scale processes now that many people don't even know what a good Pt print is supposed to look like. 
 
I commend to you an experiment:  Make some in-camera negatives with a DR above 2.1 (try to hit 2.4 for starters), and print them using the standard full-scale Pt process.  I bet you never go back to digi-neg Pt printing again, and depending on how big you think prints need to be, that you acquire one or more LARGE format cameras or learn to make good enlarged negatives in the darkroom (not so easy now that slow, blue-sensitive copy films are long gone).  If you have no option besides digital, have a service bureau make some 2.4 DR negatives with an imagesetter using your files. 
 
Best regards, 
 
etienne 
 
 
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