[LargeFormat] Pyro Tips Wanted

[Richard Knoppow]

On Mon, 29 Jul 2002 03:05:30 +0000 Pete Caluori <pcaluori@hotmail.com> wrote:

From: Clive Warren <cocam@blueyonder.co.uk>
Date: Sat, 27 Jul 2002 18:56:31 +0100

<snip>
Guess the introduction to Pyro will have to wait for a while longer -
at least until I have some appropriately exposed film and maybe also
the book. Do either of you guys have any photos on the web from Pyro
developed negs?
<snip>

Greetings Clive,

The images I posted on the discussion forum (one of an approaching mountain 
storm and the other of an abandoned ranch) were both pyro developed 
negatives.  The mountain storm was scanned in color and I never corrected 
the color, or changed it to gray scale and you can see some of the 
yellow/green stain in the image I posted.

I'm assuming you got PMK, but let me know if that's not the case.  Sodium 
metaborate is not a dangerous chemical, it is simply a balanced alkali that 
maintains a constant PH.  If memory serves me correctly it maintains a ph of 
13.2.  Any substance that's very acidic or base can be problematic if not 
handled appropriatly, but it is "not" dangerous.  As for the gloves, yes 
they are beneficial, but don't overlook your lungs!  Pyro is a very light 
powder and can become airborne very easily.  The pyro is best mixed 
outdoors.

I don't know if this is an accurate description, but Pyro developers and 
particularly PMK ane not high energy developers (PMK is a "soft working" 
developer) so you will usually see a loss in film speed.

Regards, Pete

----
  FWIW, Sodium Metaborate Octahydrate is made as follows:
100 grams Metaborate (8mol) = 45.45 grams Borax = 9.53 grams Sodium Hydroxide.

  Kodalk, which is a crystaline form is made by a process patented long ago by
Kodak. The patent numbers for those interested are 1,976,299 and 1,990,800. 
All U.S. patents are available at http://www.uspto.gov
  I think pH 13.2 is probably much too high. I don't know off the top of my
head but think its closer to about pH 9.5, certainly less than carbonate. pH
13.2 is _very_ alkaline. 

Richard Knoppow
dickburk@ix.netcom.com
Los Angeles, CA, USA