[pure-silver] Re: RC to FB
- From: Malcolm & Sylvia Brickwood <m_s.brickwood@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sat, 1 Jan 2005 09:23:30 -0800
Dave
This is interesting. I did not know about the Cyro OP-3 problem. I've
been tempted to use this kind of material myself but won't now.
I'd be interested to know which brands of paper other than Ilford and
Kodak that you may also have run your tests with. I/we normally use
Agfa or Berger.
Thanks -
Malcolm
On Jan 1, 2005, at 11:26 AM, Dave Valvo wrote:
> 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
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