How Did They Add Matrix Info To Existing Matrices?

[Wolfe]

Like this recorded in England HMV pressing. The Victor has the HMV matrix info with an added Victor catalog # and VE stamp (it's the same take.) I've heard of ways of filling in or obliterating matrix info, how did they add it?

[syncopeter]

The masters HMV and Victor sent to each other were relatively soft. So punching in additional info wouldn't be too difficult. I've also seen records with scuff marks where numbers were polished out. HMV used both full matrix and face numbers and a diamond imprint for 'electric'. For Victor originated records they punched an A before the matrix number and polished away the VE.

[Wolfe]

Must've had some kind of stamping device that could just enough of an impression. The 'B' on the Victor disc is hideously close to the grooves.

[gregbogantz]

Ordinary metal numerical and alphabet stamps are readily available and were used to stamp the metal parts. The master wax or the nitrocellulose lacquer masters were soft enough to be hand scribed with a sharp awl, or they could be stamped. Ordinary positive stamps were used on the lacquers and metal mothers, and reverse stamps were used on the metal masters and stampers. Once the earlier metal part was individually marked, that mark carried thru to all the subsequent parts made from it. At RCA records, we used a system of identifying the master lacquer take with a digit, the metal master with a letter, the metal mother with a digit, and the stamper with a letter. So the fourth stamper from the third mother from the second metal master made from the first lacquer take would carry the matrix number 1B3D appended to the selection number. Usual practice at our plants was to have the lacquer take number appended to the selection number after a dash mark. Then the master, mother, and stamper IDs were clumped together elsewhere in the leadout area.