Digital BW, The Print

Clayton, I applaud the effort that goes into running a test like that.
However, several key factors are missing from your data; Relative Humidity
during testing and resting. You may also include a UV index rating for your
test times. Neither of these is hard to do and would add tremendously to the
meaningfulness of your data. It would also not have been hard to make
several density strips that received allotted amount of sun exposure as
well; 10hrs, 20hrs, etc. The patches printed being big enough to read with a
spectro would also confirm the fade rate based on number of hours. Any glass
used would also need to have the information for its UV transmission
included in the data. Glass varies from type to type. I haven't looked
lately, but I believe the UV output of the Wilhelm lights, are known. The
yellowing of EEM may have nothing to do with the OBAs themselves and
everything to do with other chemical changes due to oxidation, or other
factors. In other words, there may not be enough of a chemical balance in
the paper to hold the reaction static.  

 

Eric

 

Eric Neilsen Photo

4101 Commerce Street, Suite 9

Dallas, TX 75226

214 827-8301

 

http://ericneilsenphotography.com

SKype ejprinter

 

  _____  

From: DigitalBlackandWhiteThePrint@yahoogroups.com
[mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Clayton
Jones
Sent: Monday, November 10, 2008 8:57 AM
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: [Digital BW] Re: 100 Hour Direct Sun Torture Test

 

Hello Richard,

>because they are normally displayed behind windows anyway, would it 
>not be better to put them under glass in the direct sun to remove 
>this contaminant factor? I appreciate that longer would be needed 
>for the test, however.

Sure, there are lots of things that with some thought could be done to
make better test conditions. I didn't set out to make an official
scientific test of some sort, it was more just to satisfy my own
curiosity. There had been a lot of talk about OBA burn off and I was
wondering how much OBAs were in VFA, especially since Epson advertises
that VFA and EEM have the same coating and EEM yellows in a few weeks.
I was looking at a test print one day and just decided to put it out
in the sun and log the time...and just see what happens.

I am continuing the testing, BTW. We have a cloudless day today and
it went out on the porch at 8:35 a.m. It should get a good long shot
today. We'll see what happens after another 100 hours.

I know it's not a good scientific test with tightly controlled
conditions, and I don't know what these 100 hours represent in Lux and
UV exposure (not to mention car and lawn mower exhaust and whatever
else it may been exposed to), but it certainly should relieve concerns
about VFA not being a good lightfast paper because it has OBAs, and
the notion that any paper with OBAs will soon turn yellow. As I
mentioned in the Paper Archivability thread, there are different types
of OBAs and the technology is improving (and, as W pointed out in the
Reichmann interview [and has been mentioned here numerous times], the
fiber silver gel papers we used for years had OBAs [and were
alpha-cellulose]). 

It's also a good testimony for K3/ABW as there is no visible fading or
color shifting. I assume we'll see some at some point. We'll see
what happens as the test progresses. 

I would encourage everyone here to do a similar test with whatever
ink/paper combination they are using. I'd love to see other user
reports posted here. I'd be willing to tabulate the results over time
and post them on my web site. I think it would be a valuable resource.

Regards,
Clayton

Info on black and white digital printing at 
http://www.cjcom. <http://www.cjcom.net/digiprnarts.htm> net/digiprnarts.htm
I-Trak 2.1 http://www.cjcom. <http://www.cjcom.net/itrak.htm> net/itrak.htm

 



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