Digital BW, The Print

Steve wrote:

>I have been using Lyson Print Guard (same product) on my HPR prints for
>framing without glazing.  It looks fine but a measured step wedge will show
>a significant shift in density post spraying, including a large drop in
>dMax.


I've seen and measured this with UltraSmooth and PremierArt Print Shield,
which, as you note, appears to be the same as Lyson Print Guard (though the
Premier Imaging people deny they are the same).

Perhaps related to this is the observation by another forum member that the
surface of smooth prints can feel a bit gritty after spraying with
PremierArt Print Shield, at least when used in hot, dry conditions.  After
looking into it, this person concluded that the solvents in the PremierArt
Print Shield were so quick to dry that the coating was starting to solidify
before hitting the print.  Lascaux Fixativ, however, uses solvents that are
less volatile and, thus, may keep its acrylic in liquid form long enough to
more effectively surround the pigment particles and lock them to the
surface.

Today I did a comparison of the two sprays on UltraSmooth.  I sprayed two
test strips of UltraSmooth with 3 coats of the 2 products.  The dmax started
at 1.61.  The test strip sprayed with PremierArt Print Shield had a dmax
drop to 1.52 and 1.51.  The test strip sprayed with Lascaux Fixativ had the
dmax drop to 1.59 and 1.57.

Perhaps related to this is my finding that PremierArt Print Shield is more
effective at reducing the bronzing on glossy papers than is the Lascaux.
With Lascaux I'll have to find a different procedure than my usual 3-4
quick, light sprays.

It appears to me that the PremierArt Print Shield tends to stay on the
surface of the print more, whereas the Lascaux appears to soak in more.  The
Lascaux solvents are, apparently, less volatile -- they evaporate slower.
In addition to the chemist's conclusions in this regard, I simply can smell
the Lascaux on the print longer.

I might add that the drop in dmax does not happen with all matte papers.
UltraSmooth is the paper that I like and use frequently that definitely does
have a tendency to have this happen.  From now on, I might be using Lascaux
on it instead of PremierArt Print Shield.  (The Lascaux is also the Rohm &
Haas B72 formula that is most highly thought of by the conservation
industry.)

Paul
www.PaulRoark.com