Digital BW, The Print

Dan and Martin,

It sounds like Royce was talking about a yellowing that is different than
the optical brightener yellowing we've become familiar with -- and
(personally) not much concerned with.  If Royce is correct, then EAM may
have more problems than I thought.

Do we know where the information on the effect of the slight acidity is
coming from?  That is, how authoritative is it?  Also, how serious is it?
If, like the OB yellowing, we're talking about 0.02 units of yellowing and
then stabilizing, then it may still not be a major issue.

Incidentally, the yellowed 1850's era prints by Gustave Le Gray at the Getty
are just spectacular.  (Not that I'm in favor of yellowing, but in those
photos its very appropriate.)

Paul
http://www.PaulRoark.com

Original messages:

Dan wrote:

>> The UC inks may last 75-100 years, but the Enhanced Matte paper will
>> begin to yellow at 30 years, at least according to Royce Bair at
>> inkjetart.com; I quote him here:
>
>> "The Enhanced Matte image permanence drop ...
>>30 years vs. 75 years (with UltraChrome inks) and the 30 years
>> vs. 100+ years (with the Archival Inks) is due to paper YELLOWING.
>> Within about 30 years,...
>> Enhanced Matte paper will yellow due to the paper's slightly acid
>> pH.  The image itself, will not start to show noticeable fading
>> until about 75 years (UltraChrome) or about 100+ years (Archival).

Martin wrote:

>... The yellowing in the Archival Matte and
>other papers with optical brightening agents is due to the OBA's loosing
>there ability to fluoresce. Robert Rex of Crane paper posted information on
>this quite some time ago. Once the OBA is exhausted and has yellowed it is
>stable and does not appear to effect paper life. ... the top silver fiber
>papers seem to use some OBA's too.