[alt-photo] Re: humidity and contrast in the palladium / platinumprocesses

[Paul Viapiano]

If you're in a dry climate or using a vacuum frame, try placing a large 
sheet of mylar/thin plastic sheet on the bed and then placing your neg/paper 
sandwich on top of that (after Jeremy's post-coating pre-exposure 
humidification). This will keep the paper from drying out during exposure 
and result in better dMax...

Yes, old FO can give you anemic prints. B&S' ferric is said to last 1-2 
years in solution but many factors, of course, can alter that. Many 
professional printers mix FO the night before a printing session and FO is 
available in premeasured mix packs for that purpose.

Paul



----- Original Message ----- 
From: "Jeremy Moore" <jeremydmoore at gmail.com>
To: "The alternative photographic processes mailing list" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Friday, May 21, 2010 7:59 AM
Subject: [alt-photo] Re: humidity and contrast in the palladium / 
platinumprocesses


> Francis,
>
> I will suggest a very easy test to see how relative humidity affects YOUR
> printing.
>
> Variable: Humidity
>
> Experimental Model:
> 1. Coat a piece of paper and immediately blow dry it (preferably with cool
> air so as not to introduce another variable, but you do want forced air)
> then expose it.
> 2. Process as normal.
> 3. Coat a 2nd sheet of paper and immediately blow dry it (dry it in the 
> same
> manner as you dried the first one). Re-humidify this paper by holding it
> over steamy water from a tap or heated water on a stove or a humidifier if
> you have one. Humidify the paper until it is as damp as you think you can
> make it without ruining your digital negative then expose it.
> 4. Process as normal.
> 5. Let both prints fully dry then compare and report back to us!
>
> Notes: Keep everything as constant as possible--even to the point of paper
> from the same batch or coating 2 halves of the same sheet. Print an image
> with long, smooth tonal scale. Include a step wedge in the prints--both a
> Stouffer if you have one and a test wedge created in Photoshop that is 
> part
> of your digital negative.
>
> On Fri, May 21, 2010 at 9:49 AM, francis schanberger 
> <frangst at gmail.com>wrote:
>
>> Dear AltList,
>>
>> What is the working relationship of relative humidity to the final 
>> contrast
>> in either a palladium developing out print or a printing out print?
>>
>> I've been struggling with contrast and have always been rather
>> laissez-faire
>> in monitoring and adjusting humidity due to the dungeon like qualities of
>> my
>> dim room.
>>
>> In regards to developers, does ammonium citrate ever get too old? Could a
>> trend of producing low contrast images independent of drop mixtures
>> indicate
>> exhausted developer? I was reading in the Weese / Sullivan "New Platinum
>> Print" book that older ferric oxalate tends to have higher not lower
>> contrast.
>>
>> -francis
>>
>>
>>
>>
>> --
>> francis schanberger
>>
>> www.frangst.com
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