Hardening salted paper and potassium dichromate

From: Fabiano Busdraghi ^lt;[email protected]>
Date: 06/20/05-08:42:56 AM Z
Message-id: <20050620144256.80869.qmail@web25507.mail.ukl.yahoo.com>

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).
I have never hardened and sized paper before the salting solution, but
reading the list you convinced me of the importanc of sizing and hardenind
and now I would like to try 3% sizing and hardening before coating the salt
I have spent several hours surfing the archive, but I still have some
question. I know that potassium chrome alum can not react with potassium
dichromate, but I know that formaldehyde and glyoxal may react whit it. I
don’t know if with the concentration used it may happen, do you have some
experience about this? I would like to use formaldehyde or glyoxal cause they
are easer to find than alum, but if there is some reaction I will search for
I’m also asking to myself if the gelatine in the salted solution must be
hardened. Do you harden it? In this case does the hardening solution must
contain 2% of NaCl?
Thank you for you answer and sorry for my not so fluent English
Best regards

HOME PAGE: http://fabiano.agriturismo-diavolino.com
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Received on Mon Jun 20 08:43:13 2005

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