Re: MOMA in Time

[karl shah-jenner <shahjen@xxxxxxxxxxxx>]

James writes:
> It's commonly thought that Nitrogen is inert. Not so, consider Nitric Acid, 
> Nitrogen Sulphide, etc among the compounds that form with Nitrogen.  What 
> makes it useful in this context is that it is not an oxidizer so it doesn't 
> readily react with the usual suspects in art and photography.

> Storage in nitrogen excludes Oxygen and other corrosive gases, doesn't 
> react at usual storage temperatures, and is cheap.

> For completely nonreactive storage, Argon is the gas of choice and is used 
> extensively in the National Archives for the most sensitive documents.


You're right - it's not what is known as 'inert' in chemistry - heleium, 
argon, neon, krypton, xenon, are the nobles for sure that are truly inert 
(so's radon, bt we'll not use that ;)  But nitrogen isn't going to form 
nitrous oxide by coming into contact with ambient air, nor will it react 
with moisture.  CO2 is also not particularly reactive..  but it WILL combine 
readily with water to form carbonic acid which is likely to cause damage. 
Nitrogen is the easiest to get, unlikely to react and as you say, it will 
displace the oxygen.  You can't use helium because the staff would spend all 
day goofing around with it.

Bromochlorodifluoromethane is also supposedly a non reactive, non toxic gas, 
formerly used for fire suppression - often used in archiving environments .. 
but it's decomposition products when it encounters extreme heat include 
hydrobromic , hydrochloric and hydrofluoric acids as well as phosgene 
(eeek!)   so yeah, the 'standard' in archival environments include a 
compound that can decompose to some extremely toxic, reactive and 
destructive byproducts.

as an aside, it's discontinuation was not so much because of this toxicity, 
but more because it was deemed an ozone depleting compound.. (though I'd 
like to know who was putting it in the upper atmosphere given it's nearly 6 
times heavier than air)  though I know the Australian Navy discontinued it 
as it killed and disabled more people than the fires they fought with the 
stuff..  but I digress.

Jan wrote:
> Polaroids shot in the 1980's .. stored in a filing cabinet in my studio and 
> they looked to be in good shape

I wrote some time back about my experience with some unexposed black and 
white polaroid I was given, dated from the 60's that proved perfectly OK to 
shoot even though it had been stored in a hot tin shed in Oz and exposed to 
extended summer temps of over 52 C (125F) and winter frosts.  the colour 
film did not fare so well, but that was the chemistry pods that had dried up 
or burst (sadly)  I'd loved to have seen how that film would have come out.

All the exposed images were however fine - and note, the chemistry 
residue/image was encased in plastic.  This was partly what led me to 
looking harder at the longevity of  RC papers over the FB's, .  and yes, 
those old test prints I did years back on RC papers were still standing up 
to being exposed to the elements some 10 years after I began the experiment 
(the FBs had long since been eaten by snails or faded away and rotted). 
Sure, that was less than  ideal  storage, but I wanted to see which stood up 
to abuse, not loving careful storage and the RCs won hands down.  The only 
RC print that faded completely was one submerged in a water tank - but that 
was expected, the copper bleached the image away before the paper 
delaminated.   We tend to look at plastics as rubbish, but we forget 
'plastic' means many, many different chemicals with the only similarity 
being they are moldable (and yes, glass IS a plastic - and a solid, not a 
liquid as that old myth suggests).   As to longevity, amber is a good 
example of just how long resinous plastics can last.

k