How to Read Matrix Numbers on Vinyl

Matrix numbers live in the deadwax: the smooth, grooveless band between the last track and the label, roughly the last 20 to 30 mm before the label edge. Flip the record to the side you want, hold it at a shallow angle under a single light source, and the characters scratched or stamped into that band will catch the light. That string is the record's manufacturing fingerprint, and reading it correctly is the first step in identifying almost any pressing.

This matters doubly for white labels and promos, where the deadwax is often the only identifying information the record has. No artist name, no track titles, no sleeve notes. Just that string.

Finding the runout area

The runout groove (also called the deadwax, the trail-off, or the lead-out) is the unmodulated spiral after the music ends. On most records it is easy to see: the playing surface has a fine matte texture from the grooves, and the runout is a smoother, shinier ring.

Look on both sides. Side A and side B almost always carry different strings, and both matter. On some 12-inch singles the etching extends right up to the label edge, so tilt carefully and check the full band. Occasionally the label itself covers part of the deadwax, in which case you transcribe what you can see.

If you are not sure whether your record is a white label, a promo, or a test pressing, our definition guide covers the distinctions, and promo, test pressing, or bootleg covers the physical tells.

How to see faint etchings

Many runout markings are shallow hand-etched scratches, barely visible head-on. Three techniques, in order of effort:

Raking light. Use a single point light source: a phone torch, a desk lamp, a bare bulb. Turn off or shield other lights in the room. Hold the record flat and tilt it slowly so the light rakes across the surface at a low angle. The etched grooves cast tiny shadows and glint while the smooth surface stays dark. Rotate the record and re-tilt, because characters read best when the light strikes them across their length.

Photograph it. Phone cameras see what eyes miss. Take a close-up with the light raking from one side, then take another with the light from the opposite side. Shallow etchings that disappear in one shot pop in the other. Shoot in burst or take several frames at slightly different angles; at least one will be readable. You can then zoom into the photo to resolve ambiguous characters.

Chalk or pencil. Old-school method: rub a white chalk or wax pencil lightly across the deadwax and blow off the excess. The pigment sits in the etching and shows as a light line against the dark vinyl. Wipe the record properly afterwards. Use this only when the other two fail, and never on a record you plan to grade as near mint.

Stamped vs hand-etched

Stamped characters come from a die: uniform depth, crisp edges, consistent font, often machine-placed in a neat line. Hand-etched characters were scratched in by the cutting engineer: uneven depth, slightly wobbly lines, varying sizes. Many deadwax areas contain both, for example a stamped catalogue number plus a hand-etched signature. Transcribe both, and note which is which if it is obvious, because the hand-etched parts are usually the engineer's own marks and are the most distinctive.

How to transcribe accurately

Write down everything, exactly as it appears, in left-to-right order. Concretely:

• Every character, including punctuation, dashes, slashes, and symbols like triangles or stars. STEAM-001-A1 is not the same string as STEAM 001 A1.
• Keep the sides separate. Label them Side A and Side B (use the etched side indicators on the record itself if present, since label printing can be wrong or absent).
• Crossed-out sections matter. Engineers sometimes cancel a rejected cut by scratching lines through it. Transcribe it as struck through, for example ~~A1~~ A2, and note that it is crossed out. A cancelled cut can be exactly the detail that distinguishes a first pressing from a recut.
• Watch for mirrored or inverted characters. A hand-etched S or 5, a 2 or Z, a 6 or a 9 viewed from the wrong angle are easy to confuse. Check each ambiguous character by rotating the record 180 degrees and looking again. If a character is genuinely unreadable, mark it as [?] rather than guessing.
• Preserve case and orientation. Some engineers etch one character upside down relative to the rest. Note it.

Why one wrong character breaks everything

Matrix strings are searched and matched as exact strings. A transcription of STEAM-001-B1 when the record says STEAM-001-BI (a capital i, not a one) returns nothing. On Unlabeled this is not just a search convenience: records are catalogued by their exact matrix string, because an unlabeled record often has no artist or title to catalogue it by. The string is the record's identity. Get it right and two copies of the same pressing connect to each other; get it wrong by one character and your record becomes a ghost.

What the parts typically mean

There is no universal standard, but runout strings usually break down into a familiar set of components. Using a generic example like STEAM-001-A1 MT.P Δ 2:

Catalogue or matrix number. The core identifier, usually assigned by the label or the cutting studio. In the example, STEAM-001. This is what ties the pressing to a release.

Side indicator. A or B, sometimes 1 or 2, occasionally X/Y or a side-specific suffix on the same base number. It tells you which side of the lacquer you are looking at.

Cut or lacquer number. The digit after the side letter, like the 1 in A1, is usually the cut number: the first lacquer cut for that side. A2 means a second cut, either because the first was rejected or for a later repress. Collectors care about this; an A1/B1 first cut often sounds different from an A3/B2 recut.

Stamper letters or numbers. Additional letters or numbers after the cut number (or stamped elsewhere in the deadwax) often track the stamper generation used to press that copy. The convention varies by plant and era, but the pattern of extra characters evolving across copies is the tell.

Mastering engineer initials or signatures. Hand-etched marks like MT.P, a stylised squiggle, or a full nickname in the deadwax are the cutting engineer signing their work. These are gold for identification: the same signature across two otherwise anonymous white labels strongly suggests the same studio cut both.

Pressing plant marks. Symbols, logos, or short codes stamped by the pressing plant, sometimes tiny. A triangle, a circled letter, a machine-stamped number block. If you learn to recognise the common ones for your era and genre, they pin down where the record was physically made even when everything else is blank.

What to do with the string

Once you have a clean transcription, you hold the record's identity. The full workflow for turning that string into an actual identification, including searching pressing databases, comparing deadwax photos, and what to try when audio-ID apps fail (they usually do on unreleased or unofficial material, because the audio simply is not in their databases), is in our flagship guide: how to identify an unknown white label record.

If the string still resolves to nothing, that is exactly the gap Unlabeled exists for. Add the record with its exact matrix string to the Archive, the public hub of unidentified records where other diggers can match deadwax, recognise signatures, or name the record from the audio preview. And if you have copies to move, you can sell on Unlabeled, where every listing is anchored to its matrix string and buyers can listen before they buy.