RE: Potentially stupid pt/pd question

[Eric Neilsen <ejnphoto@sbcglobal.net>]

Camden,  This is NOT the witness protection program, so it is OK to say the
name of the dealer. I'd call and talk to Michael Ginsberg in the NYC office.
Tell him I told you to call. 

Dmax is influenced by more than one factor; blend of PT and PD, humidity of
paper during exposure. Palladium IS FASTER at high humidity and Platinum is
faster at LOWER humidity. (That's why it is best to include a coating
mixture when asking for help)

Properly used heat will stop the coating solution from soaking into the
paper. This is why when Chris had her bleeding problem with Platine, one
would like to know what is the coating and drying procedure. They are all
connected. 

If a paper clears more slowly than others that you use, just make sure and
give it the required time or solution concentration, that is the only
concern. It is possible to make too strong of a clearing bath just like it
is possible to leave it too long in the tray. : ( 



Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
Skype ejprinter





> -----Original Message-----
> From: Camden Hardy [mailto:camden@hardyphotography.net]
> Sent: Saturday, October 14, 2006 2:53 PM
> To: alt-photo-process-l@usask.ca
> Subject: RE: Potentially stupid pt/pd question
> 
> > Why did you go with the Vellum and not the RAG? When they say they are
> the
> > same, did you ask about "whiteness", weight, ??  Whom at Legion did you
> > speak with?
> 
> Here's the story.  I placed the order through an "authorized Legion
> dealer" for the rag paper.  I got an email the next day saying that the
> rag was being discontinued and replaced with the vellum.  They said that
> it was "exactly the same" as the rag, so I went ahead and tried it.
> Clearly they were wrong, hehe.
> 
> 
> > Dmax can be compromised by not enough coating for a paper and by letting
> > in
> > soak in to deep. It may be a material that likes a lower humidity to
> start
> > with for coating.
> 
> Interesting.  I've always been told more humidity = more dmax.  I'll try
> one without humidifying and see what happens.
> 
> 
> > The pH of the substrate is only one factor in coating paper. This paper
> > may
> > need to have a more direct air stream or heat applied to it during the
> > drying process.
> 
> So does heat prevent the emulsion from absorbing into the paper too much?
> 
> 
> > How are you guessing .9? Black paper with two holes with one over the
> > known
> > value and one over the unknown value?
> 
> I had a printed step wedge with densitometry readings written on it.  I
> used that for a comparison.
> 
> 
> Should I be concerned about the slow clearing with this paper?  Is
> doubling the clearing time the right thing to do, or should I be
> increasing the strength of my clearing bath (or does it matter)?
> 
> Camden Hardy
> 
> camden[at]hardyphotography[dot]net
> http://www.hardyphotography.net
> 
> 
> >
> >> -----Original Message-----
> >> From: Don Bryant [mailto:dsbryant@bellsouth.net]
> >> Sent: Friday, October 13, 2006 6:47 PM
> >> To: alt-photo-process-l@usask.ca
> >> Subject: RE: Potentially stupid pt/pd question
> >>
> >> For clearing try using a 3 % solution of citric acid for 5 minutes
> >> directly
> >> after the developer without a water bath. Clear in Kodak hypo clearing
> >> agent
> >> @ a 1:3 dilution from stock for 5 minutes in the next two baths. Wash.
> >>
> >>
> >> -----Original Message-----
> >> From: Camden Hardy [mailto:camden@hardyphotography.net]
> >> Sent: Friday, October 13, 2006 7:10 PM
> >> To: alt-photo-process-l@usask.ca
> >> Subject: Potentially stupid pt/pd question
> >>
> >> I started calibrating my new shipment of Coventry Rag Vellum paper,
> >> which
> >> Legion assured me was te same as their Coventry Rag (thanks to Eric for
> >> the recommendation and sample).  Right out of the box, I could tell you
> >> that it's not the same.  But I swiped it with a pH pen, and at least
> >> looked acidic enough for pt/pd, so I decided to give it a try.
> >>
> >> I'll start with my workflow.  I pre-humidified the paper at 55% RH for
> a
> >> half hour, coated, then let it dry in 55% RH for another half hour.  I
> >> exposed a 31-step tablet for 6 minutes, developed in potassium oxalate
> >> (100 degrees F), cleared in hypoclear+EDTA.  This has been my normal
> >> workflow and until now proven to work well.
> >>
> >> Now here's what I'm encountering.  First of all, the Dmax is nowhere
> >> near
> >> what I would have expected.  I don't have access to a working
> >> densitometer, but I'm guessing it's about 0.9.  The other issue is that
> >> it
> >> took twice as long to clear as any other paper I've used.
> >>
> >> So here's my question.  What are the possible causes for this?  Are
> >> these
> >> issues independent of each other, or could they have the same cause?
> >>
> >> Thanks,
> >>
> >> Camden Hardy
> >>
> >> camden[at]hardyphotography[dot]net
> >> http://www.hardyphotography.net
> >>
> >>
> >
> >
> >
> >
>