78 rpm records

Elizabeth Dunford <elizabeth.rl.dunford [at] googlemail__com> writes

>I work at a historic house where there is a small but significant
>collection of 78 records belonging to the original owner of the
>house. They all date from before 1950 and are stored in albums. ...
>
>They have been stored, for at least 30 years, and potentially since
>they were bought, on shelves against a north facing wall, that has
>over the past few years suffered badly from damp. The RH of the room
>is consistently around 63%, and the paper of the albums does
>sometimes feel damp. ...
>
>The surface of the majority of the records themselves are covered
>with a white bloom ...
>...
>... What would they be made of? ...

Records get called "Vinyl" because that is what they are usually
made of: polyvinyl chloride (otherwise known as "vinyl"). Earlier
records could have been made of shellac, celluloid, wax, or rubber,
but by the 1950's it was fairly consistently vinyl.

>... What could be
>causing the bloom? ...

The bloom is probably mould, but could be degradation of the plastic
as well.

>... What sort of conditions should they ideally be
>stored in? ...

Ideally the records would be stored at 50% RH, a stable temperature
no greater than 20 deg, C, and in the dark.

Plastics in general are susceptible to UV and ordinary light, heat,
oxygen, humidity, dust and pollutants, impact/handling, mould and
vermin. Very low (sub zero) temperatures would slow the oxidative
degradation of the plastic, but would make it very brittle and
fragile, so it's usually easier to keep things at a stable but cool
room temperature.

Eliminating oxygen is also helpful, but usually difficult to
accomplish. Unless the sky is the limit, the objects are seriously
threatened, or the records are very rare and special, then this can
be omitted. If you do have some very rare and special records that
are being seriously affected by oxidation, then they could be sealed
with some Ageless and humidity control, but remember--you have to
monitor such microclimates when you create packaging like that, and
change the Ageless and humidity control when it becomes spent.

>.. Would it be detrimental to move them to drier conditions
>too quickly? ...

The records will probably handle a shift from 63% to a steady 50%
without too much problem, but if you want to be on the safe side,
you can wrap them in tissue to buffer and slow the humidity change.

>.. Can they be restored to be played?

I would prefer transferring the contents of the records to a digital
format and play the digital copy rather than the original copy when
you want to hear them. Remember to migrate your digital copies at
periodic intervals to keep up with technological changes in format
and software.

Valerie Tomlinson
Conservator
Auckland Museum
Tamaki Paenga Hira
The Domain, Private Bag 92018, Auckland 1142, New Zealand
+64 9 306 7068


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                  Conservation DistList Instance 24:48
                  Distributed: Tuesday, April 19, 2011
                       Message Id: cdl-24-48-007
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