Re: [ARSCLIST] 78rpm archaeology project

[George Brock-Nannestad <pattac@xxxxxxxx>]

From: Patent Tactics, George Brock-Nannestad

Hello,

I am forwarding this mail without the attachment, because I can see - both at 
the receiving end and at the digest that it has not gone through, and at 
least some readers would probably like to have this information. I am quite 
willing to send the attachment (37 kb of pdf file) to anyone writing me off-
list.

Kind regards,


George


------- Forwarded message follows -------
From:           	George Brock-Nannestad <pattac@xxxxxxxx>
To:             	ARSCLIST@xxxxxxxxxxxx
Subject:        	Re: [ARSCLIST] 78rpm archaeology project
Date sent:      	Sat, 29 Dec 2007 01:05:23 +0100

From: Patent Tactics, George Brock-Nannestad

Oliver Mueller-Heubach wrote:

> Perhaps the label design was stamped onto the master with wax or other 
> substance that would reject electrolysis? That way, the mold/mother could
be
> plated in gold/silver and a few layers of copper and the waxed area then 
> warmed and wiped clean. The subsequent stampers would have a raised area
of
> plated metal correlating to a negative image of the label.

----- photoengraving for printing plates was a well-known procedure. There 
can be no doubt that this process was used for creating the "etched" label on
early Edison Diamond Discs.

----- Pathé also used non-paper labels in the early days; they engraved 
directly into the metal. I have not looked closely at the edges of individual
Pathé letters, and it would also require that the white stuff be scraped out
carefully. As the engraving was a hollow so that it could be filled, it must
have been engraved in a positive. As scribing in a wax surface (the secondary
master) was materially different from engraving in copper, possibly a 
professional engraver would be able to tell from the structure of the 
engraving whether the engraving was in the wax or in the mother. Pathé later
frequently used just plain paper in their pressing and pasted the label onto
that.

----- why did I say "secondary master"? Because the original recording was on
a huge cylinder, from which the recording was mechanically transferred to 
smaller, commercially sized cylinder or a selection of variously sized
discs.

----- this also forms a neat explanation for the cutting inside-out of Pathé
disc records: the original wax cylinder and the wax disc were quite close, so
it was not possible to warm the wax without endangering the original. The wax
discs were heated beforehand, but as they cooled while being cut, the higher
cutting speed towards the outside compensated for the increase in cutting 
resistance and risk of chatter at low speeds.

----- VTMC and the Gramophone Company frequently had an electric lightbulb 
heating the inside of a cutting lathe.

----- VTMC had a lot of experimenting done for them before 1905 to get 
pigments for their labels that would tolerate the heat - including the gold.

----- for a discussion and structuring of the various markings on disc 
records, read my attachment; it is a publication that was for a few years 
available on the website of the Swedish Sound and Image Archive, but I can't
find the link now. It is called "How is discography related to the physical 
object?", and I do think I have mentioned it on this list before.

Kind regards and happy New Year,


George 

Attachments:
discographyphysical01.pdf
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