Digital BW, The Print

David,

I do agree with you. We are subjecting inkjet prints to high 
intensity testing that would destroy a silver gelatin print. It does 
give us comparison data which is better than no data but we need to 
keep it in perspective.

I would like to point out that I have noticed that the base white on 
silver fiber papers is not all that white compared to say Legion 
Photo Matte or Eclipse Satine. Silver fiber paper has a base color 
closer to Museo. So I think we may be looking at a much higher level 
of OBA in these latest ink jet papers compared to silver fiber. More 
similar to silver RC.

The thing of it is, I think we really do need the OBA's for the 
inkjet prints. With the lower Dmax of the matte ink on the matte 
papers, one of the best ways to add dynamic range is to boost the 
base white. Many years ago when testing silver papers with a 
densitometer I noted that small 0.01 changes in Dmin were very 
noticeable while large changes of 0.10 in Dmax were difficult to 
detect the further you got above 2.0.

A paper with a base reflective density of 0.06 reflects 87% of the 
light that falls on it. One with 0.04 reflects 91%. 0.02 - 96%. At 
the other end a Dmax of 2.6 reflects 0.25% of the light falling on 
it. At 2.2 - 0.63%.

I really saw this in comparing Eclipse Satine to EAM. EAM has a 
slightly stronger black but the Eclipse has a brighter, more neutral 
white. The result is that the Eclipse paper looks more vibrant.

The key with the OBA papers is going to be to use display guidelines 
similar to silver fiber. Avoid sunlight and other light sources with 
high UV content. 

In the end you have to weigh image permanence, paper permanence and 
artistic requirements, make what seems like a reasonable decision 
based on what we know, then roll the dice and get on with printing.

Martin


--- In DigitalBlackandWhiteThePrint@y..., daviddstock@e... wrote:
> I've read with interest the posts about optical brighteners in 
inkjet 
> papers. I have just a comment or two to add.
> 
> The absolute safest thing in terms of permanence is probably to 
> use papers with no optical brightening agents. However, this 
> comes with a trade-off in terms of how white the paper can be.
> 
> I think that in the long run, brighteners will be routinely used in 
> fine art inkjet papers. I base this on the history of darkroom 
> papers. It may be true that the Library of Congress wants its 
> storage materials to be OBA-free. Why not? There's nothing lost 
> for them if the paper is a little less white. But I wonder what 
their 
> position is on the photographs that may be inside those very 
> storage materials? Optical brighteners are in the prints of 
> virtually every black and white photographer since the 1960's. Are 
> the prints by Ansel Adams, Brett Weston, Paul Caponigro, etc,. 
> etc. now to be deemed "non-archival?"
> 
> We are in a shake-out period for inkjet papers. We should be 
> cautious, but not panic.
> 
> I'd like to know whether the brighteners used in, say, Legion 
> Photo Matte, are the same ones that are used in Oriental Seagull 
> or Agfa Brovira. Or are they something new and untested? I do 
> feel leery about trusting a paper with unknown brightening 
> agents unless it has at least been lab-tested. But this doesn't 
> change the overall fact that bright whites are a major aesthetic 
> issue. And in the case of fine art photography, the decision was 
> made long ago that brighteners could be safe enough, and were 
> valuable enough, to include in archival materials.
> 
> --David