[alt-photo] Re: dilution of pt/pd

Sat Jul 24 04:16:21 GMT 2010

I often buy kits from B&S for a few of reasons.

1.  The chemistry is very consistent.
2.  FO from other sources has sometimes been a problem in that it won't dissolve.
3.  B&S usually offers the "student kit" that includes the FO free.
4.  It is easy for students in my workshops to go home and order the same chemistry and get consistent results.
5.  I order developers and FO in dry packs to save on shipping and to extend the shelf life of the FO—I date the FO when I mix it with distilled water.
6.  A handy thing about the B&S FO in the 25 ml dry packs is that you can top off the bottle to the top of the label and you have exactly 25 ml of solution.  Very easy to do.

I do have Palladium powder to mix my own Palladium as per the instructions in Dick Arentz's book.

I am sure there are other suppliers for chemistry that are very good and very reliable.  

I would be interested (like David) in hearing comments about adding oxalic acid to FO and the purpose for doing so—to make it dissolve easier?  Does the FO from B&S have oxalic acid added to it?

Sources for small electronic scales both used and new are those companies that supply the ammunition reloading folks.  RCBS and others make very fine scales. I have an RCBS—works both for my reloading and for my photo chemistry.  I think it measures to .01 gram. 

I do think the discussion about molar solutions has been quite interesting and rings a bell with my high school and university chemistry classes.  Thanks to Loris, Eric and Paul for their time lending their knowledge.  If people prefer to use % solutions fine, if others prefer to use molar solutions, fine.  I wouldn't consider either to be "pointy hat."  There is nothing dangerous about acquiring knowledge and a better understanding of the universe if you wish to do so.  We don't burn witches at the stake any more, do we?

Mark Nelson
www.PrecisionDigitalNegatives.com
www.MarkINelsonPhoto.com
PDNPrint Forum @ Yahoo Groups

-----Original Message-----
From: David Ashcraft <davidashcraft at sti.net>
To: The alternative photographic processes mailing list <alt-photo-process-list at lists.altphotolist.org>
Sent: Fri, Jul 23, 2010 9:38 pm
Subject: [alt-photo] Re: dilution of pt/pd

> Who is using kits ? Why not get the salts straight from chemical > suppliers ? 

I am using premixed from B&S!  When I looked for the chems to make from scratch what I was able to find didn't impress me in savings and when I factored the time it would take to measure and mix I figured it wasn't worth it.  Perhaps the suppliers were the wrong ones but the s&h and time just didn't make sense to me. 

Although, the fact that I could try different formulas does intrigue me.  Which brings me to a question.  Could you add to an already mixed solution of FO some Oxalic acid?  Of course as long as the proportions are respected.  I ask because of the formulas I have found have the FO listed as the last ingredient and to my understanding you mix ingredients in the order listed. 

David 

On Jul 23, 2010, at 4:25 PM, Terry King wrote: 

> Well the discussion would certainly seem to confirm that  all this > chat about molarity is very pointy hat. 
> 
> 
> There are other strange happenings. 
> 
> 
> Who is using gramme scales to measure noble metal salts, or can you > measure tenths on them? Accurate scales measuring down to a tenth of > a gramme and less are not expensive and are easily available. 
> 
> 
> Who is using kits ? Why not get the salts straight from chemical > suppliers ? 
> 
> 
> Who is using molar calculations with cyanotypes, the cheapest and > simplest of processes ? 
> 
> 
> 
> 
> 
> 
> 
> 
> 'Molarity' has it's place but somebody is going to have to > demonstrate that you can get a better print for less money with less > effort to justify a departure from good old percentage calculations. 
> 
> 
> Making  good alternative process prints is simple in terms of the > process if making pictures is your objective.  You need practice and > judgement and an eye for a good picture to make really good ones.  > All this pointy hat stuff just gets in the way. 
> 
> 
> Terry 
> 
> 
> 
> 
> 
> 
> 
> 
> -----Original Message----- 
> From: Loris Medici <mail at loris.medici.name> 
> To: 'The alternative photographic processes mailing list' <alt-photo-process-list at lists.altphotolist.org> > 
> Sent: Fri, 23 Jul 2010 13:35 
> Subject: [alt-photo] Re: dilution of pt/pd 
> 
> 
> Clay, 
> 
> -----Original Message----- 
> From: alt-photo-process-list-bounces at lists.altphotolist.org On > Behalf Of 
> Clay Harmon Website 
> Sent: Friday, July 23, 2010 3:08 PM 
> To: The alternative photographic processes mailing list 
> Subject: [alt-photo] Re: dilution of pt/pd 
> 
>> This thread has been entertaining in a strange, twisted way. 
> 
> Agree. :) 
> 
> 
>> Let me see if I have this right: 
>> 
>> 1. The traditional formulas for pt/pd printing are based on >> percentages 
> and are not quite chemically balanced. In fact, there is a modest > amount of 
> waste of the 
>> pt/pd metal salt because of this imbalance. 
> 
> I've corrected this in a recent message. 
> 
> 
>> 2. It does not really make much difference in terms of print quality, 
> because there is an overabundance of metal relative to ferric > oxalate with 
> the traditional formula. 
>> It works fine, in other words. 
> 
> Well, I have to see prints to say something about that! ;) Having > balanced 
> formulae doesn't guarantee fine prints, right? 
> 
> 
>> 3. If you don't want to needlessly flush noble metal salts down the >> drain, 
> make a one-time adjustment to your formulation and keep printing. 
> 
> Yep. :) 
> 
> 
>> 4. If you don't care and don't want to think about it, and believe a 
> modest amount of waste in printing lends a sassy and insouciant 19th > century 
> flair to your 
>> printing practice, just keep doing things the way you always have. 
> 
> That was good! :) Each to their own, for sure... 
> 
> 
>> Did I get this right? 
> 
> Kinda... I thought the actual debate was on the issue of whether > talking 
> about stoichiometry and/or molarity in a public alt-process forum is > an 
> unnecessary "pointy-hat" behaviour and to "over-complicate" things, > or not. 
> Which later evolved to whether the concept of molarity does have a > use for 
> us simple / helpless / poor mortals, or not... But you can't be sure > with 
> Terry! :) 
> 
> 
> Regards, 
> Loris. 
> 
> _______________________________________________ 
> Alt-photo-process-list | http://altphotolist.org/listinfo 
> 
> 
> _______________________________________________ 
> Alt-photo-process-list | http://altphotolist.org/listinfo 
> 

_______________________________________________ 
Alt-photo-process-list | http://altphotolist.org/listinfo 