Abstract
This paper describes the process of making matrices for gramophone records in which sound is recorded on a lacquer disc by a recording machine. This disc is metallised and a stout copper shell electroformed from it. By chemical Aiming and electrodeposition a series of detachable deposits is formed in which the image is reversed in succeeding shells; finally the matrix in which the image is in male or negative form is machined to form the mould lining against which the ultimate pressed copy is moulded. Points needing special consideration are detailed and the nature and scope of each of the processes together with a description of the plant and conditions used in each are given.

This publication has 2 references indexed in Scilit: