Digital BW, The Print

Steve,

>There are several good reasons why you might want to spray an ink 
>print, for example:

>- hide bronzing,

PremierArt Print Shield and Lyson Print Guard do a good job with this.  Some
sprays do not do as well, for example Lascaux, which I use for matte papers.

>- protect the surface from fingerprints, etc,

Yes.  Most will do this.

>- add some waterproofing,

True for the glossy prints, but the matte prints need a thicker coating to
be waterproof. 

>- protect from harmful UV,

It's debatable whether this is very relevant indoors.  By the time I saw
significant benefits from the UV additives in my fluorescent light fade
testing of MIS pigments, there was also some yellowing.  I concluded it was
not worth it for indoor display and MIS pigments.  (UltraChromes may be
different.)

>- increase longevity,

Questionable.  In some tests the prints do worse when sprayed.  Usually my
fade tests don't show a lot of difference.  

The worst old photos I see, however, were primarily damaged by physical
abuse, and unsprayed or un-glazed inkjet prints may be even more susceptible
to physical damage than the traditional silver prints.  So, one has to
balance the various ways in which the print may be damaged.

I would really like to see some accelerated aging tests on coatings and
sprays.

>Should I take on trust that the chemicals sprayed on (e.g. Lyson 
>Print Guard) are actually totally harmless to the print?

No, I don't think so.

I like the fact that PremierArt has been tested by Wilhelm.  So, it's the
one I use for glossy prints, but I still am not 100% convinced it is
harmless.

For matte prints I'm using Lascaux Fixativ. (Art stores have this.  In the
U.S., Dick Blick is a source.  PermaJet is exploring this or a similar B72
approach.)

Like I said, I like to see at least some evidence that the product has been
tested.  The Rohm & Haas B72 formula used in Lascaux is probably the most
tested and accepted in the conservation industry.  For example, Ross
Merrill, Chief of Conservation at the National Gallery of Art, Washington
D.C. (USA), in a 1997 speech regarding pastel conservation said as follows
regarding fixatives:

"Today there are a number of alternatives. Krylon Acrylic Varnish B72 is
used by conservators.  [Krylon no longer makes this.  Now Lascaux is the
only B72 spray I know of.] This product will remain unchanged for 400 years,
but does have a tendency to saturate the surface.  [I'm not sure what he
means here.  Lascaux spray goes on very well.]  Grumbacher B77 varnish or
"tough film" is the same as B72, but will not saturate.  [The nozzle on the
Tuffilm  spray can is not very good.]" See
http://www.bmi.net/knapp/iapsmerrill.html 

This does not, of course, mean that the print will last as long under a
coating as it would without the coating, or that the particular solvent used
didn't do some damage before it evaporated.  I found that the Tate has used
B72 on famous old paintings, so they trust it.

>... But once sprayed -  it's permanent. 

Conservators like the B72 and similar ones because they are removable with a
solvent.  The water-borne coatings are not removable.

>Just how risky is this?

We'll only know a hundred years from now.  However, all glossy prints except
perhaps those on Epson Premium Glossy, Semigloss, Luster and Semimatte
papers will have been ruined by the acidic paper backing anyway.  A Premium
Semigloss sprayed with PremierArt did extremely well in one of my fade
tests.  Lyson Print Guard looks to be the same as PremierArt, but Premier
Imaging denies this.   

For the matte papers, the dmax reduction for most sprays is depressing.
Lascaux is among the best in this respect and is, at least by itself,
stable.  So, where a matte print is liable to be ruined by abrasion or
finger prints, I spray it with Lascaux, under the assumption that physical
damage is more likely than damage by the spray.

There are no guarantees here.  My gallery sales are un-sprayed, but they are
framed and glazed.

Good luck.

Paul
www.PaulRoark.com