RE: Pt./Pd. question acid pre-soak

Eric,

I ran the same tests, i.e. adding extra oxalic acid to the ferric
oxalate. I don't remember exactly how much I added but I did test
the pH with varying amounts added, and although the pH of oxalate
solution changed from 6.5 down to below 5.8 I did not observe any
increase in Dmax.

Sandy

>Kerik, How much "extra" oxalic acid did you try adding to the ferric when
>you ran those test? And were you able to check the pH of the solution after
>adding it?
>
>Eric Neilsen Photography
>4101 Commerce Street
>Suite 9
>Dallas, TX 75226
>http://e.neilsen.home.att.net
>http://ericneilsenphotography.com
>
>> -----Original Message-----
>> From: Kerik [mailto:kerik@kerik.com]
>> Sent: Tuesday, August 09, 2005 11:17 AM
>> To: alt-photo-process-l@sask.usask.ca
>> Subject: Re: Pt./Pd. question acid pre-soak
>>
>> With certain (apparently) highly buffered papers like Fabriano Artistico
>> Extra White, it is absolutely true. And just adding oxalic to the ferric
>> didn't have the same effect. Other papers that aren't as buffered will
>> show little or no change after being soaked in oxalic acid.
>>
>> Kerik
>>
>>
>> >> I ran test when this was talked about years ago and found little to
>> >> support it. I did not run test on a large sample of papers. I also
>> >> queried those that made the claim to see if they could also just add
>> >> some oxalic acid to their ferric and achieve the same increase in dmax.
>> >> I got no response.
>> >>
>> >> Or is it simply a pH issue? Years ago Martin Axxon had suggested to me
>> >> that he felt a lower pH paper gave a better print with PT solution.
Received on Thu Aug 11 11:18:50 2005