CD Pressing Information

They started in 1995 as Ablex, a duplication plant, then became DOCdata in 2000. Around that time they started glassmastering (mainly LP76, also LP78, possibly LA31).
In 2009 the plant was sold to Sound Performance. In 2014 it was over.
They certainly pressed discs with mould SID 73** and possibly with 4B** (maybe it was planned to change to this code but I guess it’s from another plant, maybe the one with LA31 - it’s more often found on discs with this LBR than LP76 which manufactured GMs for much more releases)

Sadly, not all plants have implemented IFPI :unamused:

1 Like

Speaking of which… there’s dozens of patents about making human readable markings on optical media…

Frequently, it is desired that the disc contain information which must be capable of being read by the human eye or by a conventional optical character reader and yet must be permanent in the sense that it cannot be altered or obscured without obvious damage to the disc. Since such information cannot be affixed to either the impressed information areas or the label areas of the disc, they must be placed in the non-informational areas of the disc such as the clamping area or in the annuli on both sides of the impressed information area(s) of the disc. Such non-impressed information includes such things as serial numbers, lot numbers, logos, vendor identification, distributor information, decorative patterns, names, bar codes, signatures, volume and issue numbers, edition numbers, dates and the like.

A standard commercially made CD-audio disc having a bisphenol A polycarbonate resin* substrate, sputtered aluminum reflective layer and nitrocellulose protective layer was positioned substrate-down in the writing chamber of a Comet YAG laser marking system manufactured by Quantrad Corporation, Torrence, Calif. The computer control of the system was programmed to print a serial number of six characters in the clamping area of the disc by passing a pulsed laser beam through the protective layer of the disc. The characters had a height of 0.1 inch. A power setting of 65% was used to mark the serial number in the metal
laser speed (traverse rate) was 1800 inches per second with a spot density of 1.

According to the present invention, there is provided a method of identifying a stamper for an optical information storage disk in order to distinguish first and second stampers from each other, the second stamper being replicated from the first stamper, each of the first and second stampers carrying recorded information signals and a printed code recorded circumferentially and representing stamper identifying information from each other, the method comprising the steps of reading the printed code in a predetermined direction, determining whether a start or stop signal of the printed code is read first, and distinguishing the first and the second stampers from each other depending on whether the start or stop signal is read first.

I don’t know if this was ever used in anything:

More stuff:

Um… there’s a bunch of patents for writing barcodes for “copy protection” type stuff… those aren’t really relevant…

There’s a lot of these… most of them seem to have been the basis of the “Burst Cutting Area”

OMG and so many more “copy protection” patents… it’s like massive entertainment corporations were obsessed with this or something… (I’m looking at a list of at least thirty more of these things)

Oh hey, it’s those shaped discs!

Oh hey, printing ink on the top of a CD, what an amazing invention!

This has some nice diagrams…

Anyway, I’m sure with a bit more time I could find some more patents on how the matrix info gets carved into the CD, but I need to work on some other stuff right now…

Ok, two more…

And this one by Disctronics Manufacturing Inc.

Manufacturing related:


A question for CD Pressing info nuts: are SIDs vs no SIDs a reason for separate releases? I thought they were?

Edit #88543478 - MusicBrainz

Plenty of places in the database I’ve seen a lack of a SID as a reason for a separate release. This edit was merging three separate releases that share a Matrix description (450991014-2 WME), but some have SIDs, one does not have SIDs, and the all have different limits as to where the black paint stops on the inner ring.

I am rubbish at describing and I am interested in opinions please. What is and is not the “same” release?

Edit: Actually - found other differences in that edit that stopped merge as CDs are painted different.

Question still stands though - where are we drawing the lines? Are we merging SIDs and No SID editions? Something that would upset Discogians, but I can see the logic. As long as we keep the main Matrix differences apart separating factories and labels?


Unless there is a difference other than SIDs I would put them in the same release. The CDs in your example are all from the same glassmaster (in this case not even different versions). They will all generate the same disc ID. Mould SIDs, even from different plants, make no difference and would be noted as annotation, but in this case, much more often there are small differences in artwork too.

If the matrix string is different only because it’s a second or third generation glass master from the same plant, then it is very likely that TOC and disc ID are still unchanged. (unless it’s a new, remastered or otherwise altered version, what would be mentioned, of course)

Mastering SIDs from different plants are another thing. These will certainly have different disc IDs and should be different. But very likely they will have other differences too.

The problem is that not all versions are sufficiently well documented, so that artwork changes can often neither be determined nor ruled out. When in doubt, I leave them separate so that they may be merged later.


SID and no SID are just a quirk of dates. In that merge example other issues made me vote no. The SIDs stood out first, but had to get the memory kicked in why I didn’t merge these last week.

Part of the reason I made a new Release in the first place is that old target of the merge is such a mess. There are three or four different editions in one heap with 8 DiscIDs attached to it. I kinda like to leave a “messy magnet” like that in the list for those who don’t really know\care. Those DiscIDs are pre-NGS and therefore not clear which edition they are for.

The third copy in there has more paint on the inner ring. My CD has a silver ring which is not visible on the other editions. The reissue paints black further into the centre of the CD.

Its good as it made me finish up my scanning of that copy that I ran out of time to do at the weekend.


If a Discogs release is assigned I would probably try to make the mess to that exact release. If not and there are merged elements from different releases, it is better to leave it as is.

I’ve noticed that. Therefore it’s distinguishable different in artwork and a separate release! :smiley:

1 Like

I normally go with that, but was also hoping the person who added all the artwork for the booklet would appear and add their CD image to those scans. The Discogs links are as random as much else about that release. There is a fairly “Interesting” editing history on that one. Including some unique pirate CD images and artwork (I am deleting those as this release is so old I didn’t want the pirate version to hijack it)

Also it does have a rather unique spine with 492 on it. Maybe that is actually genuine?

The one with the more black centre now has a bit of extra Discogs art added to show it more different to the silver ring version I have.

1 Like

Yes, in case of images or elements worth keeping, it should be kept as is. (then I would remove the wrong Discogs link instead)

Mould SID and no mould SID → merge!
These are represses of the same release. In most cases there’s no known release date for the repress. I add an annotation explaining things.
For example - a release that stretches over 15 years (–> see Annotation):

EDIT: so as not to force anyone to read the edit history: I added this release with the date of the similar release with discs MADE IN GERMANY (the attached Discogs link was the 1986 first US release, so I changed it to this year). It’s not known if it was released in 1987 as the documented MADE IN USA version is a possible repress from early-1990s.

1 Like

Yeah, agree with that. When I see a mess like that one I try and focus on “which is the best part” and clean them up. That’s why I just annotated the oddities on there initially before starting tweaking it at the weekend.

I found my post further up this thread where I was also saying the same thing. Seems sensible to me to focus on the factory. That is what causes a difference in manufacturing. Change of artwork, or how a CD is painted, is clearly in the guidelines as to separating editions.

Your Made in USA\Germany CD is not surprising. Looks like they used booklets from Europe and shipped them across the pond. (That is assuming this isn’t second hand)

A release like that one I always want to fill in all the relationships on the Release page. :nerd_face: :crazy_face: Factories, copyrights, etc. A good chunk of that annotation have proper relationships that can be used.

It is those relationships that make me keep factory changes as different Releases. A PDO Germany and PMDC Germany get split. I used to keep these on the same page, but find this is a very common split for many editors even though technically it is the same pressing plant.


It is second hand, bought from Germany, but I assume it was originally released in the US. I mentioned it because of the extended annotation, explaining how the same release was repressed through decades. (The main reason I bought this CD was to verify the disc ID, but I also bought a second-hand CD that actually traveled around the world - in 1985, JP>US>EU: Sportin’ Life :grin:)

No other plant has such beautifully presented company credits … but on the matrix side. So I consider them one release unless there are artwork differences, which mostly don’t exist. Although this makes it impossible to credit the company at all (“made/pressed by”). But I’ll leave that to Discogs.

1 Like

I am glad it is not just me who does that… an interesting way to expand a music collection though :rofl:

1 Like

I’ve seen so many of these split up that I have always followed that pattern. I do own two CDs of one artist with the only difference being the change from PDO to PMDC and had originally put them as a single combined release, but credited both labels in the “pressed by” relationships. Some point in the last few years I split them after a forum discussion. (I wonder if I can find it?)

Ah - the fun of multiple opinions…

Edit: Not going to feel guilty about that split. Just pulled those CDs off the shelf and spotted a physical manufacturing difference. That PDO CD is old enough to not have the raised ring on the inner to keep it off the desk. i.e. one of those CDs that sticks to the scanner glass due to static and you need a plunger to get off :rofl:


I didn’t find anything about it either. I wouldn’t do that, although it’s certainly a borderline case. The company credits are clearly readable and understandable. But in principle, a “pressed by” credit does not have to be exclusive to one company. There could be multiple pressed by credits for one release, for the companies which repressed it too.

they don’t even detach from the glass when the scanner is tilted 90°. That never happens with newer CDs - that’s progress :joy:

1 Like

Especially as PMDC would press CDs which still have Made by PDO on them…

You need a little suction cup for those old CDs


Oh, it’s funny that my releases tagged as flat cd, were made by PDO, indeed.

1 Like

This may well be a PDO only thing then. I had a couple of 1980s EMI Swindon disks in hand yesterday - and they have ridges. Nimbus and other older CDs all have ridges.

I’ve just pulled a random half dozen PDO Germany CDs from my shelf - all flat. Once they change to PMDC the ridge appears. PDO UK doing the same flat thing

Edit: Got me looking… I don’t own it, but the earliest Japanese CD I know of is this Dark Side of the Moon from 1983. You can see the ring is present. I think PDO Germany & UK just missed this feature off. Probably trying to save money (and there are many other not


No no maybe not only PDO.
Buy it’s funny.
I just tagged 2 random CD of mine but remember seeing flat CD more often at the beginning of CD.


I figure this thread would be as good a place to ask as any…

if a release has IFPI codes, does that automatically mean it was released after 1994 or whenever those became the standard, or were they around before then?

the release in question, has a release date on Discogs of 1991, which is the later (℗) copyright date

1 Like

IFPI was introduced in 1994, therefore a disc with SID codes was not manufactured until 1994.
However, sometimes CDs that were pressed later can also be considered as belonging to an older release. It requires that artwork is completely unchanged and the content is exactly the same. This is usually the case if there is an earlier version without SID codes from the same manufacturer.

In the example, that doesn’t seem to be the case. Glass mastering in Uden started mid-1990s and even if there were no artwork changes, the content will be changed a bit anyway. It’s not a simple repress, even if the re-release date was kept in the copyright notice. 1991 was probably the copyright date of the first CD release.
Unfortunately the Discogs version doesn’t offer much information.


I would focus on the His Masters Voice DRM logo - when did CDs first appear like this? How old is that series? Similar with the CDs - did the red logo appear on EMI Classics CDs in 1991?

What I do notice on an initial glance is this look like an Alsdorf CD from 1991. The “Made in Germany” stamp on the front. Which could imply your CD is based on those, but swapped manufacture to Holland.

A barcode wildcard search brings up EMI CDs of 1990 and an undated:*&type=release&limit=25&method=advanced

Notice how the one CD disc image in there has the DRM logo on. Your CD is an EMI Classic logo.

Maybe 1991 isn’t far off. UDEN was starting pressing that year, and this feels like it may be a CD taken from Alsdorf to be printed there with minimal changes in the artwork. Yet still printing with Made in Germany on it three years later is oddly lazy for a Dutch pressing. Usually that would change to Made in Holland. A puzzle

1 Like