Digital BW, The Print

Todd,
IMHO, permanence of a print should relate to the archivalness of the 
paper AND the archivalness of the ink/coating combination.  
At this point i have not seen any data on the effect of OBA's and 
fillers on coating/ink combinations.  Whereas i think their effect, 
and the effet of wood vs. cotton, on paper permanence is fairly well 
documented.
I have seen plenty of data on coating/ink combination and their 
effect on permanence.  
Uncoated papers (like Arches CP/HP, Fabriano, Rives BFK, and 
Somerset) seem to have better light stability with dye based inks.  
these papers usually are sized with gelatin, starch, PVA, etc.  It 
also seems that papers using a swellable polymer seem to offer better 
light stability with dye-based inks.
regarding pigment based inks, to obtain a similar gamut that would be 
achievable with a dye based ink, you would definitely need to utilize 
a coated sheet.  I have printed an Oce watercolor sheet on our 2000P 
here in the office and was not as impressed as printing our ETFA, 
Museo, Hahnemuhle or Somerset E. papers.  These coatings usually 
include different types of pigments and chemicals--the formulae of 
each paper are different--which enable the pigment of the ink to 
adhere to more to the surface of the substrate (instead of wicking 
into the paper.
i hope this helps somewhat (for further questions, please contact me 
off-list)
thanks for your attention,
robert rex
crane & co

--- In DigitalBlackandWhiteThePrint@y..., Todd Flashner <tflash@e...> 
wrote:
> Robert
> 
> Your posts are always very informative, thanks. You've spoken in 
the past
> about OBs and now buffering agents, do you have any think to share 
with us
> about the effect of the paper's inkjet receptive coating on 
permanence? It
> would be particularly helpful to be able to ascertain which papers 
would be
> most suitable for dye inks, which for pigments, and which for 
hybrid blends.
> 
> Todd Flashner
> 
> > Excellent post, Martin!
> > the only thing i would add is that the "amount" of buffering 
agents
> > tend to affect the archivalness of a paper.  Libary of Congress
> > standards indicate that they consider an archival paper to have 
not
> > more than 3-5% of fillers (fillers include buffering agents like
> > CaCO3, pigments like titanium dioxide or silica) by weight. (my
> > memory may be off here, but i think i posted the LoC website in an
> > earlier post and Martin bookmarked it in the Files section of this
> > list.
> > Fillers are measured by the amount of ash resulting by burning the
> > paper. 
> > Museo contains 2.8-3.3% filler or buffering agent (Calcium 
carbonate
> > in Museo's case; this is the most common alkaline buffering 
agent--
> > arches, etc have used this for centuries.)  We have tested some
> > papers--internally--with an ash content as high as 10%.
> > hope this helps,
> > robert rex
> > crane & co