[alt-photo] Re: PVA addn. to pt/pd soln.

[Loris Medici]

I see thanks. BTW, another change besides the procedure of drying paper is
reducing the PVA...

Now, I'm not completely sure what PVA does here, but in my knowing, (in the
context of pt/pd) bleeding is mostly caused by bad absorption of sensitizer
into the paper's fibers. If the most of the sensitizer sits on top of the
paper instead of being trapped in between the paper's fibers, you'll loose
some of the image in the development/wash water, which is more pronounced in
the highlights, because the lost / remainder ratio is higher there. COT320
is already a pretty hard paper, therefore additional sizing / emulsification
additions should worsen the situtation. (Logically.)

I'd try to double coat the same amnt. of sensitizer diluted 1:1 with
distilled water, or to add few drops of distilled water (the max. amnt. that
will let you coat the paper without floating it and necessitate too much
brushing - to not risk abrading the surface), or adding a little surfactant
(Tween, Ilfotol?) to the mix...

Anyway, since you're OK now, all above is not more valuable than mere
rhetoric...

Regards,
Loris.

-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org On Behalf Of BOB
KISS
Sent: Wednesday, December 16, 2009 4:49 PM
To: alt-photo-process-list at lists.altphotolist.org
Subject: [alt-photo] Re: PVA addn. to pt/pd soln.

DEAR LORIS & DIANA,
	Many years ago when I started pt/pd printing I wasn't getting the
D-max I hoped for using on the Lenox paper I was using at that time.
Someone on the list suggested a drop or two of PVA in the coating solution
and it worked wonders:  Good D-max and no bleeding.
	Well, as J. R. R. Tolkien said, "Old Hobbits die hard!" so I
continued using it when I switched to Cranes Platinotype again getting
excellent results:  Good D-max and no bleeding.  I simply continued since I
have been mostly using COT 320 for the last 5 years.  Excellent D-max and no
bleeding before this last week.  This strongly indicates that something has
changed just recently.  
	I have changed the following and the bleeding is gone:
1) I made certain that the paper was completely dry before re-humidifying.
I had gotten a little lazy about this.  
2) I more carefully controlled my Dev temp (I let it get a little too warm
on the print that bled).  
3) I reduced the PVA by one drop per 11X14 coating volume.  
	As my 3 year old daughter says, "Awww gone!"  No more bleeding.  
	Do I need the PVA with COT 320?  Perhaps not but it isn't "broken"
so I am not going to "fix it".  The bleeding could just as easily been from
not fully drying the paper as from anything else.  
		HOLIDAY CHEERS!
			BOB
	

-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org On Behalf Of
Diana Bloomfield
Sent: Wednesday, December 16, 2009 10:02 AM
To: alt-photo-process-list at lists.altphotolist.org
Subject: [alt-photo] Re: PVA addn. to pt/pd soln.

I was wondering the exact same thing.  I'm really curious.  I've never heard
of using PVA to coat pt/pd-- and especially, as Loris says, on a  
paper like COT320.   I would think that alone might be the source of  
any coating/bleeding problem.  ??

Diana

On Dec 16, 2009, at 7:43 AM, Loris Medici wrote:

> What is the purpose of adding PVA into pt/pd solution - especially for 
> a hard paper like COT320?
>
> Regards,
> Loris.
>
> -----Original Message-----
> From: alt-photo-process-list-bounces at lists.altphotolist.org On Behalf 
> Of BOB KISS
> Sent: Wednesday, December 16, 2009 2:24 PM
> To: alt-photo-process-list at lists.altphotolist.org
> Subject: [alt-photo] Re: BLEEDIN' PT/PD PRINTS
>
> ...
> I use 2 drops of PVA in enough soln to coat an 11X14 sheet of COT 320.  
> Good or bad?
> ...
>
> -----Original Message-----
> From: alt-photo-process-list-bounces at lists.altphotolist.org On Behalf 
> Of Christina Anderson
> Sent: Tuesday, December 15, 2009 10:49 AM
> To: alt-photo-process-list at lists.altphotolist.org
> Subject: [alt-photo] Re: BLEEDIN' PT/PD PRINTS
>
> Bob,
> How much PVA are you adding to the coating solution?
> ...