This is a well researched piece of information.
It's always nice to get a professional's opinion in this matter.

Paul Turney
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-----Original Message-----
From: Goran Finnberg [mailto:[log in to unmask]]
Sent: Saturday, December 12, 2009 02:06 PM
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 atthat time mid 70┤s.All the production people called the parts Father, Mother and Son. Includingcalls 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 partsFather, Mother and Son in the tree day seminar I went to in the 70┤s. Andthis continued when they began producing presses for CD production when Ihelped out some friends who started Logos AB here in Gothenburg which wasonce a cassette duplicating plant but later on started producing CD┤s.Sonopress in Germany, and many more too many to list, also referred them tobe Father, Mother and Son.In fact dealing with hundreds upon hundreds of companies professionallyinvolved with mass duplication of Vinyl or CD disks here in Europe I havealways seen, Father, Mother and Son, to be used as description of the threestages used to provide a replicated LP/CD disk to be used as the finalcarrier to be sold in the retail shop.Using Google with the keywords:Record Pressing Father mother son stamperTurned up several hundred hits to numerous to list here but I looked at afew: etched glass master is not used to stamp discs itself, but is used tocreate a metal stamper through a process called electroforming. A layer ofnickle is effectively grown onto the disc, transferring the etched pits onthe glass into bumps in the metal disc to produce a 'father' disc. For veryshort CD pressing runs, this father can be used as the direct stamper, butit is more common to produce one or more 'mother' discs from the father, andthen several 'sons' from each mother. The sons are used as stampers toproduce the raw plastic CD discs------------------------- a process known as "electroforming", the metalised glass master has alayer of nickel grown onto its silver surface by immersion in a tank ofnickel sulphamate solution. This sheet of nickel - referred to as the"father" - is subsequently removed from the silver. The father is a reverseimage of the data and could be used to stamp discs. However, it is not.Instead, the father is returned to the electroforming tank where anotherlayer of nickel is grown and subsequently removed to create a "mother". Themother undergoes the same process to produce a "stamper" (sometimes referredto 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 thefather stamper. "-------------------------[0106]Further, in the same manner as a procedure of obtaining the motherstamper from the father stamper, an oxide film is formed on a surface of themother stamper, and an Ni film is electroformed and released, therebyobtaining a son stamper having the same patterns of the father stamper.--------------------------- the exposed areas are developed away by conventional methods toproduce pits, a rigid metal negative to the master, called the Father orMaster stamper, is produced by an electoplating process (see Figure 2).A multiple positive image Mother may be electroplated from the Fatherstamper. In turn, negative image Son stampers are plated from each Mother toproduce multiple copies of the original master.Mass replication of the source begins by mounting a Father or Son in amolding press. Melted plastic is injected into the cavity and allowed tocool. The pits from the stamper are accurately reproduced in a plasticsubstrate, forming the original positive image.--------------------------, the newly applied metal layer is pulled apart from the disc master,which is put aside. The metal layer, or father, contains a negativeimpression of the disc master track; in other words, the track on the metallayer is an exact replica, but in reverse, of the track on the disc master.* The metal father then undergoes further electroforming to produce oneor more mothers, which are simply metal layers that again have positiveimpressions of the original disc master track. Using the same electroformingprocess, each mother then produces a son (also called a stamper) with anegative impression of the track. It is the son that is then used to createthe 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 andforms the desired outside diameter.-------------------------------------- to a preferred embodiment of the invention, a first metallic (Ni)mold tool (father) is made which is a duplicate of a master substrate, thena resin mold tool (mother) is made which is a duplicate of the firstmetallic mold tool and finally a second metallic (Ni) mold tool (son) ismade which is a duplicate of the resin mold tool. Both the father and sonmay be referred to a │stamper▓.---------------------------------------As I have also had to deal with Georg Neumann record cutting equipment thenall the descriptions dealing with what happens after the laquer being cutthen the descriptive words Father, Mother, Son was always used.Nowadays I am helping a young man who have bought an old Neumann VMS66cutter here in Gothenburg and he recently added record plating equipment tohis 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 theprevious owner. 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:MATRIX:A metal part, originally produced from a laquer master, by theelectrodeposition 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 andmanufacture of gramophone records.Gilbert Briggs, owner of Wharfedale loudspeakers, England in his book A to Zin 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 thattime.And I just consider the use of the above to be as common in certain quartersas Father, Mother, Son is to me.None of them is wrong one should just be aware that depending on where youare in the word that different words are used to describe the exact sameprocess.I could just use the word "Working Matrix" to describe the Son or Stamperand old ones in the production industry would understand at once what Imeant.Work part can be used too in a pinch....;-)-- Best regards,Goran FinnbergThe Mastering Room ABGoteborgSwedenE-mail: [log in to unmask] from the mistakes of others, you can never live long enough tomake them all yourself. - John Luther