This is very interesting.  I have noticed three things about these
references and your discussion.  
1)  All of these are relatively recent.
2)  They tend to be European.
3)  They are mainly discussing CD replication

CDs are injection moulded, and in this process the discs are not really
pressed or "stamped", they are moulded when the liquid is injected into
the already closed press.  It could almost be said that calling the
mould a stamper is incorrect!!  Although the same is true with injection
moulded styrene and vinyl records, because the metal part is the same
whether it is placed in a compression moulding or injection moulding
press, during the days of grooved records it was called a stamper in
either case. (Of course Edison called his cylinder masters "moulds", but
I don't remember what the Edison disc masters were called --  the
Diamond Disc manufacturing process was called "printing" not "pressing".

Considering that the older printed sources you referenced to which call
the part "stamper" are pre-CD, it is possible that the use of "son" came
about during the CD era when no compression moulding -- or stamping --
was being done.  On the other hand, your personal stories about the
earlier use of son in Sweden are interesting and they are at the same
level as my anecdotal experience of hearing only the use of stamper! 
That's why I asked about printed sources since I could provide those
beyond my anecdotes. 

Since the CD was developed by European and Japanese firms, if these
companies used "son", it probably caught on quicker in Europe.  I
haven't heard American CD replicators using "son", only "stamper", but
you do show some American sources.  However these sources seem to be
from companies and people which come only from a CD background without
having prior experience in grooved records.  (Remember a month ago when
we had a reference to a modern California vinyl pressing plant website
which had a weird description about 78s being made from shellac sheets
glued to a heavy paper core -- how much do the younger modern "experts"
know about the history of their industry?)   

I might mention that the use of the term "father" is also rare -- but
not unknown -- in my experience, but the term "mother" is almost
universal!!  I have never understood why mother came to be so common
while father is rare and son was non-existent to me before this
discussion.  The female metal part was given a descriptive female name
by just about everyone, but why not the mail metal parts?  And I am
rather surprised that none of the discussion included the term "shell"
which was seemingly the official term of the Gramophone Co. to describe
the metal positive pulled from the original wax.  This term is used from
the very beginning of the company but I don't see it used by Victor, at
least not as much.

I am eager to hear from my friend George Brock-Nannestad about this
discussion since he had done a lot of study of the technical
documentation in Europe in probably every language.  Is he on vacation,
or pouring thru a basement full of books and photocopies trying to
research the facts before answering?  

Mike Biel  [log in to unmask]  

From: Goran Finnberg <[log in to unmask]>

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,
owned by EMI for most of its life, 1974 to 1989.

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

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

Toolex-Alpha once world leader in vinyl pressing equipment called the
Father, Mother and Son in the tree day seminar I went to in the 70´s.
this continued when they began producing presses for CD production when
helped out some friends who started Logos AB here in Gothenburg which
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
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
always seen, Father, Mother and Son, to be used as description of the
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

The etched glass master is not used to stamp discs itself, but is used
create a metal stamper through a process called electroforming. A layer
nickle is effectively grown onto the disc, transferring the etched pits
the glass into bumps in the metal disc to produce a 'father' disc. For
short CD pressing runs, this father can be used as the direct stamper,
it is more common to produce one or more 'mother' discs from the father,
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
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".
mother undergoes the same process to produce a "stamper" (sometimes
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
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
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
layer is an exact replica, but in reverse, of the track on the disc
* 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
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
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
mold tool (father) is made which is a duplicate of a master substrate,
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
may be referred to a ³stamper².


As I have also had to deal with Georg Neumann record cutting equipment
all the descriptions dealing with what happens after the laquer being
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
his services and without no promting from me he called the process
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

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


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
as Father, Mother, Son is to me.

None of them is wrong one should just be aware that depending on where
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
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