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

[David Ashcraft]

> 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.
>
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