[alt-photo] Re: pt/pd differences in exposure methods

[EJ Photo]

Paul, Over the years there has been much discussion on different exposure
units, and everything under the sun. With not only the quality of light but
the quantity of light being important, they alone don't determine the speed
of the coated paper. The film or substrate that holds the resist, negative
both digital and traditional, blocks UV light as does the glass. it is a
complicated set of variables. The glass types can change their UV blocking
characteristics while keeping the same name or label. Rigorous testing over
all the possible sources has not to my knowledge been done with certainty. 

You also have the moisture content, and make up of FO, AFO, and paper types.


Mike Ware did put out a paper on platinum printing many years back that did
specify yield based on certain UV output. It did hold true to my
observations, but I never tried to match, make equivalent controls, etc.
Best advise I can offer on that is keep notes, and use your findings for
your specific set of contact frames, glass, negatives and ink sets. 

NuArc is a brand, but not a specific lamp; there are several that work. 

Eric Neilsen
Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
 
www.ericneilsenphotography.com
skype me with ejprinter
www.ericneilsenphotography.com/forum1
Let's Talk Photography
 
-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Paul Viapiano
Sent: Tuesday, June 29, 2010 6:28 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: pt/pd differences in exposure methods

No, Jeremy, I don't.


----- 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: Tuesday, June 29, 2010 4:24 PM
Subject: [alt-photo] Re: pt/pd differences in exposure methods


> Paul, do you have a densitometer to measure the difference in reflective
> dMax?
>
> On Jun 29, 2010 5:44 PM, "Paul Viapiano" <viapiano at pacbell.net> wrote:
>
> Has anyone compared exposure methods and the differences in results?
>
> I seem to get deeper blacks when exposing in the sun than using the NuArc.
> Even using a separate custom curve for each method, the sun gives me a
> better black, more contrasty result...
>
> Don't get me wrong, the results are very good, but the edge goes to the 
> sun
> prints.
>
> Paul
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