Re: sodium citrate, ammonium citrate, bleeding of borders

I'll jump in here. The acidity influences the clearing of residual ferric
oxalate from the paper. If your clearing baths are at all basic, you risk
creating insoluble iron that gets locked into the fibers of the paper. My
water here in Houston in the summer has a pH of 7.8 to 8.0. I noticed that I
was having a difficult time in clearing prints if I dropped them into a plain
water bath right after the developer and right before the first clearing bath.
So my procedure now is to put my prints straight into a bath of citric acid
directly from the developer. My clearing problems went away completely.

The relevance here is that if your developer has a pH above 7.0, you risk
creating the same clearing problem with the developer.

Clay

Quoting "Christina Z. Anderson" <zphoto@montana.net>:

> 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>
> >>>
> >
>
>
>

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.