Arlene,
>I found that Kamar varnish , about 2-3 coats gave a beautiful smooth satin
>finish on HPR when I used MIS quadtones, but with the UT7 inks, the
>Kamar gives a slight haze to the print, as well as a gritty surface,
>obliterating details in the shadows.
The historic Damar (?) coatings yellowed. I'm not sure what the new
synthetic ones are.
>It seems that the pairing of paper and coating must also must
>include the ink.
You may be right. It's too bad because it makes the choice rather
complicated.
> In the long run, I'm going for no coating and frames with
>glass.
The snapshots on the refrigerator, however, may need some protection. Also,
photos in a scrapbook are liable to get finger prints on them unless they
are under mylar (which interferes with viewing) or have a protective spray.
Right now I'm leaning toward PremierArt for glossy and B72 (Lascaux and
maybe another supplier) for matte. But, one size does not fit all very
well.
> On the spur of the moment I sprayed a failed print with Minwax clear
>semi-gloss polyurethane. It is gorgeous - but I wouldn't take a chance on
>it.
No, all the spray polyurethanes are aromatic, and they will all yellow --
very significantly. The only polyurethanes that don't yellow are the
aliphatic ones. These are water-based, like the Hydrocote I was
experimenting with last year.
There is a lot of R&D going into advanced clear coats. I'm convinced we'll
have much better coatings in the future. However, right now we're just not
there.
I was looking for one that was an oxygen and humidity barrier, but none of
the current coatings that accomplish this have the longevity we're looking
for. The coatings we're using are actually rather permeable to the gases
that attack our pigs, with the water-borne acrylics being the most
permeable. There are aliphatic epoxies, which are good water barriers, but
they tend to yellow and are brittle. The current super coats are the 2
component polyurethanes, but even aliphatic versions of that are said to
yellow slightly.
So, for now, I'm sure we'll hear all sorts of claims, but aside from some
useful physical protection and UV blocking for outdoor display, that
ultimate oxygen and humidity barrier that would really extend the life of
our pigs does not appear to exist.
Paul
www.PaulRoark.com