Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Walker Blackwell <forums@...> wrote:
>
> John, although there hasn't been any study on it, I really think it's  
> a pollution issue. I think there is something in the air in Chicago  
> that kills HPR 308. Maybe Tyler has it out there too. I haven't ever  
> seen yellowing happen in VT or inside Black Point in Chicago (and we  
> have prints in there that have sat around for 5 or 6 years.) But that  
> surface reacts to something and so-far there hasn't been much of a  
> study on it.

I tend to agree with this assessment. The severe discoloration problem has been witnessed and reported on HPR the most, but that anecdotal experience can be in part if not entirely explained by the popularity of this matte paper. There is a pretty strong connection with certain non-acrylic adhesives, and this adhesive off-gassing problem which induces the bright yellow (possibly elemental sulfur), light bleachable reaction has been reported on other matte papers as well. Whether those papers are simply rebranded HN materials and hence the problem confined to just one manufacture is not known, but I rather suspect that high sensitivity to gaseous pollutants is inherent in the nature of the microporous coating. This is an industry issue which has been around for over 10 years and apparently no one has gotten to the bottom of it yet. BTW, I've never seen reports of the bright yellow stains occurring on semigloss or glossy microporous papers, only the matte microporous papers. Anyone here seen it on a glossy photo type microporous paper?