Re: sodium citrate, ammonium citrate, bleeding of borders

Chris,

Other responses by Clay and Eric reflect my understanding of the pH
issue as it relates to staining. With both kallitype and palladium
printing, and regardless of whether I am using ammonium citrate,
sodium citrate or potassium oxalate I get staining that is very
difficult or impossible to clear if the developer pH gets over about
pH 7.0. And with most papers, the pH of the developer increases as
you send more paper through, I guess because most papers have a
slight base buffer. So to prevent staining I also have to replenish
the developer on a regular basis, which I do by adding back about
50-100 ml of fresh solution for every 100 square inches of paper that
goes through the developer, though more appears to be needed with the
citrates than with potassium oxalate.

Not sure about the bleeding issue since this is something I have not
experienced. It could be an old developer issue, or a paper issue,
just don't know.

As for your experience re: speed and color, I generally agree. In my
experience ammonium citrate gives the coldest tones, followed by
sodium citrate, and potassium oxalate gives the warmest tones. Also,
for warmer tones you can heat the potassium oxalate. As for speed,
the major difference I have observed is between the citrates and
potassium oxalate, as I get about a 1/2 stop increase in speed with
the later. Between ammonium and sodium citrate, perhaps I have not
tested it as closely as you since I did not observe any difference.

Sandy

>Sandy,
>In what way does the acidity have a big impact on printing? In the
>way the print looks finally or in the way it processes? I think a
>while back you had said that you get staining if the developer does
>not stay acid but I am not seeing that happen.
>
>BTW, Sam also told me you've tested am and sod side by side and may
>know the speed/dif between the two. Does your result match
>mine--sod being a bit lower contrast, 1/4 stop slower maybe at most,
>and a bit yellower in tone?
>Chris
>
>>I use sodium citrate for printing kallitype, and sometime with
>>palladium (though for palladium I prefer potassium oxalate). What I
>>use is Trisodium Citrate, C6H5Na3O7, 258.07. When mixed with
>>distilled water the resulting pH is about 7.0. I bring this down to
>>about pH 6.0 by adding more citric acid to the mix, and this has a
>>big impact on printing.
>
>
>One could also add citric acid to an ammonium
>>citrate solution to reduce pH.
>>
>>In any event, I do agree that it would be best to test these two
>>solutions at the same pH to create a valid comparison in printing
>>characteristics, because pH does make a big difference, and you
>>especially want to avoid allowing the solutions to become slightly
>>base.
>>
>>
>>Sandy
>>
>>
>>
>>
>>>Oh pooh, Roger! I threw away the jar. I knew I should've kept it.
>>>
>>>I got it from Tri-Ess when it was in business, but since they closed
>>>I threw away the catalog, too, so I can't even check back. But if
>>>someone has an old catalog of TriEss it would be in there. I know
>>>it was written on the label, anyway.
>>>I had no idea there were three types!
>>>Chris
>>>----- Original Message ----- From: "permadocument" <info@permadocument.be>
>>>To: <alt-photo-process-l@usask.ca>
>>>Sent: Monday, July 24, 2006 2:18 AM
>>>Subject: Re: sodium citrate, ammonium citrate, bleeding of borders
>>>
>>>>Dear Chris,
>>>>
>>>>Can you tell us what sodium citrate you used; monosodium (pH= 3,4-4,0),
>>>>disodium (pH=5,0) or trisodium (pH=7,5-9,0)?
>>>>Thanks,
>>>>Roger
>>>>
>>>>--
>>>>Roger Kockaerts
>>>>Permadocument - pH7
>>>>Rue des Balkans, 7
>>>>B-1180 Brussels
>>>>Tel.:32-2-347 66 76
>>>>Fax: 32-2-344 43 04
>>>>TVA: BE 0438 246 889
>>>>web page: <http://www.permadocument.be>
Received on 07/24/06-10:52:34 AM Z