From: Patent Tactics, Laust Brock-Nannestad
-- in George's absence: he knows about this discussion and will contribute
late when he is back. He hopes the problem still exists at the end of the
> 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. "
> 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 │stamper▓.
> 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