[pure-silver] Re: RC to FB
- From: "Dave Valvo" <dvalvo@xxxxxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 1 Jan 2005 11:26:36 -0800
Peter, some good questions. I did some tests about 6 years ago sealing
prints and running accelerated aging tests. I will share a few points from
the tests.
In some circumstances plastic glazing is recommended in place of glass. In
fact, before I knew better, I used to recommend the use of Cyro OP-3 acrylic
sheet since it was so white and clear, is light weight and has excellent UV
absorbing properties. It did reduce brightener degradation in the tests.
But now I know that it is also very porous to atmospheric gases and any
pollutant will go right through it. I changed that recommendation. So if
you have an old Kodak print storage document with OP-3 in it ..toss it.
Glass is better.
There is a mat product called "Artcare" produced by Bainbridge. It has
molecular sieves that absorb bad gases and thus protect a print. The tests
I ran did not stress the mat board enough so I can't claim if it helps or
doesn't. Bainbridge tests however make the product look good. The boards
are made of alpha cellulose not cotton rag. ( although they may have
extended "artcare" into their cotton rag products by now.)
NOTE: Red spots are seen in RC papers and are caused by peroxides generated
by the TiO2 in the resin layer. The peroxides attack the silver causing
shiny spots.
Some points from the tests are:
* 28 day test will cause red spots in papers without antioxidants. (means
the test works)
* Mechanized process is worse than tray processing for red spots and OB loss
in RC papers.
* Fiber base papers are not susceptible to red spots.
* Red spots did not occur on untoned Kodak and Ilford papers.
* Selenium toning eliminates the concern for red spots in all papers, even
those without AO's.
* Wrapping in aluminum had no affect.
* OB loss due to exposure to light is worse in RC papers than in FB papers.
Kodak and Ilford papers were best.
* Selenium toning does not reduce OB loss.
* OP-3 reduces OB loss.
* Artcare did not reduce OB loss.
* Silver in RC and FB will oxidize due to atmospheric gases, such as paint
fumes, new rugs and pollution.
(previous tests showed 30 day waiting period is required after
painting a room before re-hanging silver artwork,)
* Selenium toning will protect images in both RC and FB papers from
oxidation.
* OP-3 is not as good as glass protecting images from atmospheric attack.
* Artcare ability to absorb bad atmospheric gases...inconclusive.
* Crazing concerns in Kodak and Ilford RC papers seems to be eliminated.
Dave
----- Original Message -----
From: "Peter De Smidt" <pdesmidt@xxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, December 31, 2004 1:43 PM
Subject: [pure-silver] Re: RC to FB
>
> Ryuji Suzuki wrote: For those who give proper (which I mean very close to
> thepossible best) processing to prints, the expected action of archival
> toning is to protect image forming grains from deterioration due to
> environmental pollutants.
> Would encapsulating the mat board and print be a good way to protect from
> environmental pollutants? I once read that if you want to put a print in a
> bathroom or kitchen, that you should frame the dry-mounted print with
glass
> as the backing board, instead of using archival corrugated board. You then
> band the edge of the glass, mat board, print, mat board, glass sandwich
with
> aluminum foil, which is then taped (with Mylar tape) to form a vapor
> barrier.The extra glass would add weight and cost, and one would have to
be
> careful that the tape doesn't peek out from under the frame. Does this
> soundlike a viable way to minimize print deterioration due to
environmental
> factors?
>
> -Peter De Smidt
>
>
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