Digital BW, The Print

Paul, will you be making UT curves for the 1280 and some RC papers 
like Premium Semi-Gloss?

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark" 
<paul.roark@v...> wrote:
> John,
> 
> >It looks like PremierArt Printshield is being proposed as a
> >spray for papers like Epson Semi-Gloss to eliminate bronzing.
> >Sounds good.  You get a glossy print with good dmax and no
> >bronzing and a protective surface.
> 
> Yes, add to this a Wilhelm dark storage life of over 200 years, and 
it makes
> an interesting package.
> 
> >But with EEM and the like, the Mayer rod with polyurethane seems
> >to give the same results.  And even though it's a little more
> >involved than the spray can, EEM is WAY cheaper than glossy papers.
> 
> EEM is acidic, having a dark storage life of 110 years, according 
to Wilhelm
> -- and that is under ideal conditions.  When acidic materials have 
been
> encapsulated, they have in some tests deteriorated 10 times as 
fast.  If the
> acidic H+ ions are cannot escape, they will have nothing to do but 
attack
> the un-buffered EEM paper.  So, to get an equivalent life, you'd 
have to go
> with a buffered cotton paper.  The price comparison is then not as 
good.
> 
> >So why use the RC paper with Printsheild approach?
> 
> There are a number of reasons.  
> 
> One is the existence of the Wilhelm tests of the PremierArt spray.  
I don't
> have one for the polyurethane coating I was doing.  
> 
> I was not able to scale up the Mayer rod.  Some claim to have been
> successful with 16x20, but I never saw one.  I would have gone to a 
thicker
> glass and continued to try if I had not been intrigued by the 
barrier
> papers.  So, one reason is that I think I'll be able to scale this 
process
> up to any size.
> 
> I think the carbon pigment may be best protected if it is entirely
> encapsulated.  In my high humidity fade tests, the polyurethane 
coated test
> strip did worse than one that was not coated.  I think the reason 
is that
> humidity was getting into the print from the back and then was not 
dried out
> the way the non-coated test strip was.
> 
> I am most impressed with the solvent based coatings in terms of 
their
> ability to surround the particles and protect them.  The solvent 
based
> materials are in liquid form when they hit the pigments.  The liquid
> surrounds the particle and then hardens.  The water borne materials 
just lay
> on top.  It appears to be the difference between water-based paint 
and
> oil-based.  The later soak in and stick better.  The solvent based 
sprays
> are going to do a better job of encapsulating the pigment particles,
> protecting them from the environment, and sticking them to the 
paper.  A
> tech person with one of the acrylic companies also said that the
> solvent-based UV protective sprays are much more effective at UV 
protection
> than the water-borne materials.
> 
> With the 4000, we'll be able to go with either paper easily.  I'm 
not
> abandoning the matte papers, but it is time to optimize the B&W 
systems for
> both now.
> 
> The barrier (RC) papers may be the easiest, least capital-intensive 
way to
> get very durable, high dynamic range display prints.  At least it 
is worth
> exploring.
> 
> Paul
> www.PaulRoark.com