Digital BW, The Print

Well, there's more to this I think.

First, it's not just the UV frequencies that do damage to artworks on 
paper. Visible light does a fair amount of damage on it's own. The 
intensity is also important. This is why interior carpets still fade - 
direct sunlight still fades, even when you lop off all the UV. I've got 
carpet fade in a room where I've got double glazed low-E glass. The 
carpet gets little UV, but it gets full-intensity direct sunlight during 
the afternoons.

Second, glass breaks. Drop a framed print and you not only loose the 
frame and the glass, you almost certainly loose the artwork being 
"protected" by the frame. It'll be cut to pieces.

Third, using one of the anti-reflective coated glasses for framing big 
works is amazingly expensive. But I'm sure this has nothing to do with 
why some framers and framing suppliers like it so much ;-)

Fourth, big glass for framing big works is really heavy. This makes 
framing difficult, and hanging the frame awkward. And awkward is a 
recipe for dropping a frame (see "second" above).

Fifth, some lighting gives off a fair amount of UV. MR-16 quartz 
halogens can do this if you don't put a filter in front of them. If you 
are lighting your prints directly (spot lights) this can be a problem if 
your glazing doesn't knock down the UV.

I've asked my local art museum what they use and why. The answer was 
OP-3 UV acrylic, mostly because of "second" above. Where the art work is 
valuable, you can't allow it to be hurt in an accident.

Of course, YMMV. I'm still using OP-3 myself, and don't see any real 
reason to change. I put money into decent lighting (tracks, 30 degree 
angle to avoid reflections) instead. I don't have a problem with 
"dulling" but will acknowledge some warming - either yellowing from the 
OP-3 or from the 3000K tungsten halogen bulbs.
--
Bruce Watson


Steve Kale wrote:

> I was chatting with a UK glass supplier yesterday about glazing for 
> some prints.  He made a comment that I thought was interesting with 
> respect to UV filtering.  Ordinary glass will apparently filter 
> approximately 40-45% of UV light.  So in a modern house/building with 
> double-glazed windows more than 64% of the outside UV light doesn't 
> even make it indoors - even in  an interior with many windows.  (He 
> actually said 80%, ie 2 x 40%, but I assume the relevant maths is 
> multiplicative rather than additive.)
>
> He rated the UV filtering of Denglass Water White, for example, at 
> 40%.  Schott Miroguard Plus he rated at 84%.  (Apparently Denglass is 
> a Schott product made under license.)  In the context of interior 
> exhibited prints we chatted about what was more important, UV 
> filtering or the clarity and light transmission of the print glazing.  
> He was very much in favour of the latter - poor quality glazing (even 
> if UV) can dull (by blocking too much light) and colour shift prints.