Lars Gaustad wrote:
> Hi,
> I have a student who would like to conclude her bachelor degree with work on degradation, cleaning and replay of recordable aluminum disks.

Usually when we refer to discs just as "aluminum discs" we think first 
of the embossed  uncoated  aluminum discs that were used in the late 
1920s through 1934 and occasionally after.  I'm not sure if these were 
used much in Europe, and from the following I suppose that this is not 
what your student means.

>  So I ask you for hints on reference literature on instantaneous disks ( acetates, lacquers, whatever your choice of term might be) in general, and aluminum disks specifically. 
> lars gaustad  senior preservation advisor  national library of norway
Because aluminum was only one of the bases used for coated discs (such 
as glass, steel, plastic.and fibre)  I generally wouldn't suggest the 
word "aluminum" be used as a general description word.  "Lacquer" or 
"lacquer coated" is preferred.  "Acetate" is incorrect because the discs 
were not coated with cellulose acetate, it was cellulose nitrate, so 
nitrate should have been the name but it was rarely used.  I discuss in 
my Ph.D. dissertation "The Making and Use of Recordings in Broadcasting 
Before 1936" why broadcasters fell into the habit of calling them 
acetates -- it was because there were discs PRESSED of acetate in the 
early and mid-30s (such as Flexo pressings for Brunswick transcriptions 
and the flexible clay colored discs for World Broadcasting System) and 
the special needles used for playing them were also used for lacquers.  
I have come across examples of pressed acetate discs with vinegar smell, 
and this is IMPOSSIBLE with lacquer discs because they WEREN'T acetate, 
so this is an important reason why not to call lacquer discs "acetate".

There were several good guides published in the era of the discs that 
are good guides to how they were treated at the time.  AudioDevices 
published several editions of  "How To Make Good Recordings" and there 
were two editions of "The Recording and Reproduction of Sound" by Oliver 
Read which have good information on the cutting of the discs.  Playback 
methods have vastly changed, of course, and the preservation and 
cleaning of the discs was not an issue back then.  I should note that 
there were other types of "soft-cut" discs used in Europe in the 30s and 
war years such as gelatin as floppy and coated on glass or aluminum, 
Decelith, etc. that are rarely discussed in American works.  It is 
especially important to be able to note the gelatin coated discs from 
around 1933 to 35 because the coating is water soluble.   I've only seen 
examples in a private collection in England, but I suppose they exist 

The subject is complicated, and even more so in Europe if your student 
wants to be all-inclusive.  If the only interest is in the standard most 
often encountered lacquer coated aluminum base disc, there are a lot of 
publications and postings that discuss these.  ARSC-AAA published an 
extensive preservation manual about 20 years ago, and there are a number 
of web sites that have pages about the topic.  But there is a lot of 
mis-information floating around out there.

Mike Biel   [log in to unmask]