The secret history of messages etched into records runout groove

Practically since day one, the inside track or runout groove of a vinyl record or 78rpm disc has been the domain of the matrix number, an alphanumerical code either stamped or handwritten into the wax to help pressing plants assign the correct stamper and label to each side of the record.

Extra digits often refer to the cut or take of a particular record, while some plants or cutting engineers will assign their own signatures to the space.

Far from an exact science, matrix numbers will often be taken into consideration by collectors, either as proof of first pressings or sought-after alternate takes and re-cuts.

All this code though is rather formal in contrast to the hidden messages which have since jostled for space alongside their more conventional brethren in the runout groove.

Sometimes other messages are etched... or hidden as Jack White's or other artists/discs...

Intriguing...