Re: Platinum/Palladium & Paper Speed

most of papers have an alkaline reserve that brakes the action of acidic processes, the neutrality of the AP makes a normal image, as the time where most of rag papers were neutral.
  ----- Original Message -----
  From: Ender100@aol.com
  To: alt-photo-process-l@usask.ca
  Sent: Monday, May 29, 2006 8:37 PM
  Subject: Re: Platinum/Palladium & Paper Speed

  Hi Loris,

  Thanks for your response.

  Absorption sounds like a possibility too. How bout paper thickness? Sizing?

  Best Wishes,
  Mark Nelson

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  In a message dated 5/29/06 1:08:46 PM, mail@loris.medici.name writes:

    Hi Mark,

    I won't approach this issue from the pt/pd perspective:

    I think apart being chemical (undoubtedly paper's chemistry has great
    effect over the results), it may also be strongly related to
    absorbtion - more absorbent papers being slower. What is your
    experience with contrast? I mean; have you found that slower papers
    exhibit consistently lower or higher contrast? (I'd bet for:
    "consistently higher contrast")

    My logic is based on my classic (and new) Cyanotype experience: when
    you double coat the speed drops and contrast increases... Double
    coating = using more sensitizer per given coating area -> absorbent
    paper also uses more sensitizer per given coating area... FWIW, my
    exposure times are more or less the same for 4 or 5 different papers I
    have used since I started making Cyanotypes and I always double coat
    classic cyanotypes (single coat new cyanotypes) + I always use the
    same amnt. of sensitizer per given coating area (lightsource is the
    same).

    Just my 2 cents.

    Regards,
    Loris.

    ----- Message from Ender100@aol.com ---------
        Date: Mon, 29 May 2006 12:42:24 -0400 (EDT)
        From: Ender100@aol.com
    Reply-To: alt-photo-process-l@usask.ca
    Subject: Platinum/Palladium & Paper Speed
          To: alt-photo-process-l@usask.ca

> Has anyone proposed a reason why some papers print faster or slower
    (shorter
> or longer exposure times) than others when printing with
    Platinum/Palladium?
>
>
> It would seem to be some chemical related issue, such as buffering
    or ph of
> the paper, but I am only guessing.
>
> I would assume this is also true for many other processes?
>
> Can anyone suggest a reading reference on this?
>
> Thanks in advance.
>
> Best Wishes,
> Mark Nelson
Received on 05/29/06-12:54:47 PM Z