RE: Hardening salted paper and potassium dichromate

I don't know Rives bfk, but if I Google it I see it described "acid free",
"pH neutral", etc. This almost certainly means it's alkaline buffered;
paper buffering is usually with carbonate, so your sensitised paper will
contain some silver carbonate as well as chloride, and this could be the
cause of your problem. Try a non-buffered paper and see if it makes a
difference. Whatman is good for salt, or maybe a cartridge paper - as long
as it isn't buffered.

Liam

-----Original Message-----
From: Fabiano Busdraghi [mailto:fabusdr@yahoo.it]
Sent: 20 June 2005 16:22
To: alt-photo-process-l@sask.usask.ca
Subject: RE: Hardening salted paper and potassium dichromate

because I'have tried it (I have tried to say it in my first message, but my
english...), but after one minute all step of the colour palette are light
brown, and I have to expose 9 minute more to have dmax...
no potassium dicromate simply does not work with my epson 2100 and standard
inks on pictorico ohp. I'll try lower dichromate concentration, but some
will
be necessary. to increase contrast maybe I would have to change light, or
other parameters.
anyway thank you for you answer loris
fabiano

--- Loris Medici <loris_medici@mynet.com> ha scritto:

>
> Why don't you try first with the lowest contast emulsion mix (read as:
> no potassium dichromate)? I haven't done salt prints before but AFAIK
> adding contrast agents to the emulsion decreases the speed of it
> considerably... What printer are you using? If it's an Epson with OEM
> dye inks then the UV density of red dye should be more than enough for
> making salted paper prints without the addition of contrast agent (was
> it log 3.6?). Also, I remember reading somewhere that the Ammonium salt
> is slightly more contrasty than the Sodium salt...
>
> Regards,
> Loris.
>
> > -----Original Message-----
> > From: Fabiano Busdraghi [mailto:fabusdr@yahoo.it]
> > Sent: Monday, June 20, 2005 5:43 PM
> > To: alt-photo-process-l@sask.usask.ca
> > Subject: Hardening salted paper and potassium dichromate
> >
> >
> > Hi,
> > after printing several traditional negatives on salted paper
> > I tried pdn, that I had successfully experimented with
> > multigrade fb paper. Usually I use a 2% NaCl and 1% gelatine
> > solution and a 12% silver nitrate, 6% citric acid sensitizer.
> > I brush coat both solutions. Paper is Rives bfk. Using my
> > black light tubes my standard printing time is about 10
> > minutes, but after 1 minutes any step of the colour density
> > range palette is still white. Adding potassium dichromate
> > (0.2%) to the salted solution I than have a standard
> > printing time of about two minutes and still pure white steps
> > (I'm searching the minimum amount of potassium dichromate to
> > print whit pdn but this is another story).
> > ...
>
>

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Received on Mon Jun 20 11:20:26 2005