Picture discs can be made by using different materials: cardboard, 
paper, shellac, plastic, glass, aluminum, vinyl, cellulose - that is to 
say, just about any medium that can be used to reproduce grooved sounds.
The first 78rpm picture discs were made in Germany (and France) some 110 
years ago. They were printed picture postcards covered with a 
transparent film into which the grooves were pressed. The story is 
detailed on my website
http://www.lotz-verlag.de/Online-Disco-Phonocards.html
Just try the various links for images of the patent issued to Thomas in 
1904, and scans of specimen.
Similar technologies were revived in Germany during the 1920s for 10" 
discs (I have test pressings).
The first 33rpm picture discs were manufactured by RCA Victor in March 1933
The Nazi records mentioned (including those featuring Hitler's portrait 
or the swastica flag - I showed those at last year's Rochester ARSC 
meeting when discussing the German record label book) were 20cm and 25cm 
cardboad discs distributed by Nationaler Schallplattendienst from Berlin 
for election campaigns in 1932.
Der Laut records mentioned also manufactured 30cm diameter picture disc, 
also cardboad.
German manufacturers experimented with all sorts of carriers during that 
period. For instance, Metallophon used a metal core from 1931, covered 
with layers of cellulose ester.
The first microgroove picture discs were made in Germany during the mid 
1950s by BB-Schallplatten.
The picture disc technology was refined over the vinyl era, when they 
were mostly made of five layers. "Two transparent sheets of plastic film 
are placed in the mould of the press, one on the bottom, the other on 
the top. A punched-out sheet of paper, printed on one side only, is then 
placed over each of the sheets of film. The middle of the sandwich is 
then filled with a layer of heated vinyl granulates. The layers are 
fused together in the machine under heat and pressure" [Peter Bastine: 
Extraordinary Records, Taschen, Cologne, 2009].
Rainer

-- 
Dr. Rainer E. Lotz
Rotdornweg 81
53177 Bonn (Germany)

Tel: 0049-228-352808
Fax: 0049-228-365142
Web: www.lotz-verlag.de