Ok eric.
I was intersting exclusively to the reaction of the platinum emulsion, not at the development because I work by humidification.
I have a project of platinum prints big size (M²) the next year, and there, I would attend more actively to inherent development problems.
thank you for your interest.
Marc Bruhat
20 rue Caillaux
75013 Paris
33 01 45 82 22 60
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@usask.ca
Sent: Tuesday, May 30, 2006 11:00 PM
Subject: RE: Platinum/Palladium & Paper Speed
Marc, Several papers that I have tested the oxalic acid soak on required a new sizing be put on the paper; gelatin would be a good example. If not, the coating solution would just soak right into the paper. There is no way one can spread it around without it and least not that I have seen.
Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
214-827-8301
http://ericneilsenphotography.com
Skype : ejprinter
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From: marc bruhat [mailto:m.bruhat@free.fr]
Sent: Tuesday, May 30, 2006 2:55 PM
To: alt-photo-process-l@usask.ca
Subject: Re: Platinum/Palladium & Paper Speed
Eric,
Tests on different thicknesses of a same paper seems me a good tracks.
But it is necessary to add "data" of absoption of the sensitive product, and this, without gelatin coating added.
I do not understand presicely your question but I have washed my paper very carefully after having acidified it (could you explain resize?)
Marc Bruhat
20 rue Caillaux
75013 Paris
33 01 45 82 22 60
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@usask.ca
Sent: Tuesday, May 30, 2006 4:06 PM
Subject: RE: Platinum/Palladium & Paper Speed
Marc, There is no doubt that the buffers and sizing are part of the speed equation. To keep the variables down to a manageable level, the same paper at different weights may be one way to test thickness as a factor. However as you change thickness there might be more available buffering agent to the coating, not because there is a different density but rather just because there is more to interact with the coating.
What did you resize your paper with after the acid treatment?
Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://ericneilsenphotography.com
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From: marc bruhat [mailto:m.bruhat@free.fr]
Sent: Tuesday, May 30, 2006 12:43 AM
To: alt-photo-process-l@usask.ca
Subject: Re: Platinum/Palladium & Paper Speed
I made a platinum order in 1993 on "Arches Aquarelle" 300 gr "satin" just before they coat an alakaline reserve .
During order, they change their paper.
Blacks were far more clear.
I have had to make three acidic baths to 30°C to balance the PH of the paper, and I have been able to finish the order under applause.
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@usask.ca
Sent: Tuesday, May 30, 2006 5:02 AM
Subject: RE: Platinum/Palladium & Paper Speed
If water facilitates the process and a thicker piece of paper holds more water, is it faster? Does the water slow the process, thinner is faster as the water is removed from the arena?
In my memory bank of coating experiences, a thinner coating is faster, but also more prone to bronzing. I don't recall though, if I tested that with different mixes or if I just increased the volume and that decreased the bronzing with a particular paper.
And I also think it important to say whether it is in factory condition and has the paper been soaked, treated, or otherwise altered with the exception of the coating solution. If "all other variables are held constant", does that just mean that if a paper was available as a 180gm paper and as a 300gm paper you consider that constant?
If you do find something in Dick's book, please site the page(s).
Sounds like you have some time on your hands : ) have fun
Eric
Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://ericneilsenphotography.com
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From: Ender100@aol.com [mailto:Ender100@aol.com]
Sent: Monday, May 29, 2006 1:34 PM
To: alt-photo-process-l@usask.ca
Subject: Re: Platinum/Palladium & Paper Speed
Hi Eric,
All good questions, but I am referring to just differences in paper speed given all other variables are held constant. I'm not asking because it is a problematic issue for me, my question is just out of curiousity. What factors affect the speed of different papers? Now that I think of it, I think DIck Arentz has some reference to this in Platinum & Palladium Printing, Second Edition, I'll read that and report back. But in the meantime, are there other processes where all variables kept constant, except paper, where different papers exhibit different speeds?
Thanks!
Best Wishes,
Mark Nelson
To NSA: If you are reading this email, could you please search your database for my other black sock?
Precision Digital Negatives--The Book
PDNPrint Forum at Yahoo Groups
www.MarkINelsonPhoto.com
In a message dated 5/29/06 1:24:13 PM, e.neilsen@worldnet.att.net writes:
Mark, One of the primary chemicals that is part of the process is water. I'd check to see how it is being affected by the procedures being used. Was the paper humidified before exposure? What type of contact frame was used to make the exposure? Vacuum or split back? Sealed unsealed with regard to a vapor barrier between the glass/neg/paper/backing? Heat level during exposure?
Which of these inhibit the movement of water, and which accelerate or facilitate it? Is it localized?
And then there is the light source. or UV rays. How are they passing through the paper? During exposure as well as after when the image is formed and being revealed to the eye as a reflected image?
If it were true in other processes, are they also using FO, and/or AFO?
Have you put this question to Mike Ware? He at least did some scientific study of the PT/PD process which was published years back. Perhaps, he can give you some additional insights.
Eric
Received on 05/30/06-11:24:32 PM Z
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