From: Judy Seigel (jseigel@panix.com)
Date: 08/17/02-10:40:55 PM Z
On Fri, 16 Aug 2002, Sandy King wrote:
>
> >... Have you got that blue paper, or
> >whatever they call it, to put in with? When calculating change or no
> >change would be good to have a benchmark. I have a pack of it but it's
> >old... think I got it from.... Light Impressions? Or other conservation
> >source.
>
>
> What is blue paper? As for bench marks I plan to also include in the
> tests a real platinum and a real carbon print, plus I will also note
> the reading for paper base, that is, the areas that receive no
> emulsion and no exposure.
It's called Blue Wool. I got mine from Golden Acrylics & it was for
testing lightfastness of their colors. I'm not planning to use it & would
send it to you (will anyway if you say the word), but it's probably about
10 years old & seems to me not worth risk of using outdated material,
given all the labor involved -- & I doubt very expensive.
You put one of the blue wool patches with each test and leave one in the
dark, so you have an absolute to measure your changes against, and can
also measure the changes of variables in the series against each other
better than you could simply by eye -- like a 21 step gives absolutes you
can't get by printing from a pictorial negative. Without that, as Roger
said, all you would know for sure would be the fading relative to a
particular platinum print, and some platinum prints do fade. I remember
Peter Marshall sent some platinums (I'm pretty sure it was him & them, was
a while back) out for blue wools & results showed some fading. You
outline a much needed long awaited really important test... If the blue
wool is still available (I haven't heard it mentioned lately) would add a
lot & not be a lot more trouble.
Try the sources listed in section #1 of Post=Factory Sources and Services,
"Archival Materials & Storage." Some of them have "hot lines" &/or free
consultation services -- as I recall Gaylord ... could probably tell the
story instantly.
> I have not consulted with any photo conservators but have read
> Wilhem's work and consider myself fairly conversant on the issues.
So I'm sticking my neck out again guessing, but isn't Wilhelm doing photo
color, that is, factory paper in plastic using dyes? I would expect the
issues, chemistry, etc., to be quite different.
> There are clearly some concerns that this test will not address but I
> think it will address the most important ones that I see as specific
> to kallitype, i.e., the impact of residual iron on light stability,
> and the degree to which toning provides greater archival qualities to
> a kallitype.
You won't know the "degree" for sure or be able to quantify it without a
benchmark, or so I would suppose.
> I chose the car because the prints will be subject to a lot of light
> all year round, and they will also be subject to a lot of humidity
> and heat. For example, my car is left closed with the windows up
> about 90% of the time, and temperatures often rise up to well over
> 120F. As for using the oven, wife won't have any of that.
Now a wild "what if" -- what if that car window glass has a UV barrier
built in that house window glass and regular framing glass don't -- oo la
la! For someone who wants to add to the sum total of human knowledge,
that's another test. But what a dandy thought -- all the photogs who have
tested something or other by keeping it in their car for X years.... Don't
you love it?
best,
Judy
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