Thank you for spending the time to write this well
considered bit of history on the terminology of
CD/LP production in Europe.

Very much enjoyed it, and appreciate your active
membership on the ARSC List.

Eric Jacobs

The Audio Archive, Inc.
tel: 408.221.2128
fax: 408.549.9867
mailto:[log in to unmask]
Disc and Tape Audio Transfer Services and Preservation Consulting

-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]]On Behalf Of Goran Finnberg
Sent: Saturday, December 12, 2009 6:07 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Cataloging of metal parts

Michael Biel:

> Actually I don't think that anyone has ever heard of it.

> I have read hundreds of books, articles, instruction
> manuals, guidebooks, etc. about recording techniques
> and technology dating from all eras of the industry,
> but have never seen anything relating the stamper to
> the word "son".  Can you cite me some specific sources
> in print that use this term?  I'm not saying that it
> has never been used, but it must be quite uncommon, at
> least in English.

I have worked as a consultant to Skandinaviska Grammofon AB in Amal, Sweden,
owned by EMI for most of its life, 1974 to 1989.

It was supposed to be the largest vinyl record pressing plant in Europe at
that time mid 70┤s.

All the production people called the parts Father, Mother and Son. Including
calls to EMI England, or when EMI people turned up at the factory in Sweden.

Toolex-Alpha once world leader in vinyl pressing equipment called the parts
Father, Mother and Son in the tree day seminar I went to in the 70┤s. And
this continued when they began producing presses for CD production when I
helped out some friends who started Logos AB here in Gothenburg which was
once a cassette duplicating plant but later on started producing CD┤s.

Sonopress in Germany, and many more too many to list, also referred them to
be Father, Mother and Son.

In fact dealing with hundreds upon hundreds of companies professionally
involved with mass duplication of Vinyl or CD disks here in Europe  I have
always seen, Father, Mother and Son, to be used as description of the three
stages used to provide a replicated LP/CD disk to be used as the final
carrier to be sold in the retail shop.

Using Google with the keywords:

Record Pressing Father mother son stamper

Turned up several hundred hits to numerous to list here but I looked at a

The etched glass master is not used to stamp discs itself, but is used to
create a metal stamper through a process called electroforming. A layer of
nickle is effectively grown onto the disc, transferring the etched pits on
the glass into bumps in the metal disc to produce a 'father' disc. For very
short CD pressing runs, this father can be used as the direct stamper, but
it is more common to produce one or more 'mother' discs from the father, and
then several 'sons' from each mother. The sons are used as stampers to
produce the raw plastic CD discs


In a process known as "electroforming", the metalised glass master has a
layer of nickel grown onto its silver surface by immersion in a tank of
nickel sulphamate solution. This sheet of nickel - referred to as the
"father" - is subsequently removed from the silver. The father is a reverse
image of the data and could be used to stamp discs. However, it is not.
Instead, the father is returned to the electroforming tank where another
layer of nickel is grown and subsequently removed to create a "mother". The
mother undergoes the same process to produce a "stamper" (sometimes referred
to as a "son"). Several stampers can be grown from the same mother.
CD Pit Structure


" Also, a mother stamper or a son stamper may be manufactured from the
father stamper. "


[0106]Further, in the same manner as a procedure of obtaining the mother
stamper from the father stamper, an oxide film is formed on a surface of the
mother stamper, and an Ni film is electroformed and released, thereby
obtaining a son stamper having the same patterns of the father stamper.


After the exposed areas are developed away by conventional methods to
produce pits, a rigid metal negative to the master, called the Father or
Master stamper, is produced by an electoplating process (see Figure 2).

A multiple positive image Mother may be electroplated from the Father
stamper. In turn, negative image Son stampers are plated from each Mother to
produce multiple copies of the original master.

Mass replication of the source begins by mounting a Father or Son in a
molding press. Melted plastic is injected into the cavity and allowed to
cool. The pits from the stamper are accurately reproduced in a plastic
substrate, forming the original positive image.


Next, the newly applied metal layer is pulled apart from the disc master,
which is put aside. The metal layer, or father, contains a negative
impression of the disc master track; in other words, the track on the metal
layer is an exact replica, but in reverse, of the track on the disc master.
*    The metal father then undergoes further electroforming to produce one
or more mothers, which are simply metal layers that again have positive
impressions of the original disc master track. Using the same electroforming
process, each mother then produces a son (also called a stamper) with a
negative impression of the track. It is the son that is then used to create
the actual CD.
*    After being separated from the mother, the metal son is rinsed, dried,
polished and put in a punching machine that cuts out the center hole and
forms the desired outside diameter.


According to a preferred embodiment of the invention, a first metallic (Ni)
mold tool (father) is made which is a duplicate of a master substrate, then
a resin mold tool (mother) is made which is a duplicate of the first
metallic mold tool and finally a second metallic (Ni) mold tool (son) is
made which is a duplicate of the resin mold tool. Both the father and son
may be referred to a │stamper▓.


As I have also had to deal with Georg Neumann record cutting equipment then
all the descriptions dealing with what happens after the laquer being cut
then the descriptive words Father, Mother, Son was always used.

Nowadays I am helping a young man who have bought an old Neumann VMS66
cutter here in Gothenburg and he recently added record plating equipment to
his services and without no promting from me he called the process Father,
Mother Son when he spoke about this process as he had learnt it from the
previous owner.

So to me at least, this is universally used here in most parts of Europe.

But looking in the 1973 edition of the EMI Technical Glossary page M2 says:


A metal part, originally produced from a laquer master, by the
electrodeposition of nickel:

1. Metal Master (Negative).
2. Metal Mother (Positive).
3. Metal Stamper (Negative).

It is stated at the very beginning:

The terms used here are the most commonly used in the recording and
manufacture of gramophone records.

Gilbert Briggs, owner of Wharfedale loudspeakers, England in his book A to Z
in audio, 11/1960 states on page 166:

The sequence of record processing is as follows:

1.Laquer original - positive.
2 Metal Master - negative.
3 Metal Mother - positive.
4 Metal stamper, known as the working matrix - negative;
5 pressing - positive.

The above presumably comes from the DECCA/London pressing plant at that

And I just consider the use of the above to be as common in certain quarters
as Father, Mother, Son is to me.

None of them is wrong one should just be aware that depending on where you
are in the word that different words are used to describe the exact same

I could just use the word "Working Matrix" to describe the Son or Stamper
and old ones in the production industry would understand at once what I

Work part can be used too in a pinch....;-)


Best regards,

Goran Finnberg
The Mastering Room AB

E-mail: [log in to unmask]

Learn from the mistakes of others, you can never live long enough to
make them all yourself.    -   John Luther