RE: Potentially stupid pt/pd question

[Eric Neilsen <ejnphoto@sbcglobal.net>]

> -----Original Message-----
> From: Camden Hardy [mailto:camden@hardyphotography.net]
> Sent: Sunday, October 15, 2006 2:44 AM
> To: alt-photo-process-l@usask.ca
> Subject: RE: Potentially stupid pt/pd question
> 
> > Camden,  This is NOT the witness protection program, so it is OK to say
> > the
> > name of the dealer.
> 
> True.  However, I've always had great experiences with this company, and
> the last thing I want to do is badmouth them on the alt photo list.  I'd
> like to think it was an isolated incident, which it may or may not be, and
> move on.  If I have any future troubles with this merchant, I'll let
> everyone know.  Until then, I'll keep their name anonymous.
> 
> As far as the paper itself goes, the coventry vellum is actually quite
> nice in terms of look and feel.  As long as I can get a decent print with
> it, I'll be happy.  :)
>

You may have gotten good service before and you'll probably get good service
in the future, but in the process of withholding the name, you may be
setting someone else up for poor service in regards to papers. 

 
> 
> > 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)
> 
> I didn't know the ratio of pt to pd made a difference in dmax, although
> it's not all that surprising to me.  I've been using Dick Arentz's pt/pd
> contrast mixtures, and in this case the 2s mixture.  This translates to a
> ratio of 6 pd:6 ferric oxalate:1 Na2 (5%).
>

So other than the Na2, there is NO PT in your prints. The ratio (or use of
or not) can help to say why you are seeing a particular effect; like reverse
of the blacks with only PD. The blend of PT and PD, along with humidity,
will produce a print that has certain speed and contrast characteristics.  

 
> 
> > Properly used heat will stop the coating solution from soaking into the
> > paper.
> 
> What exactly do you mean by properly used heat?
>

Properly used the heat will stop the penetration of the coating solution
into the paper with no fog or grain. Improper use can cause fog by cooking
the paper with an airstream that is too hot. 

 
> 
> > 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. : (
> 
> Could you elaborate on this?  What are the consequences of each?  Which do
> you think I should stick with?  Is there an easy way to tell which is the
> better choice for this paper, aside from appearance (from an archival
> standpoint)?
> 
You can find out what is in the paper and judging by your experience with
your distributor, I'd call Legion directly or look it up on the web site but
I don't know if they have it up on the site. 

You can soften the paper and make it extremely hard to handle without
damaging either the whole piece or opening up the door for surface
abrasions.  If you are using an acid bath to clear, you may damage the paper
leaving it hard and brittle. 




Eric Neilsen Photography
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