Last Updated: December 25, 2017
1. Flat Edge
The very earliest 12″ microgroove Blue Note LPs (1956/7) were pressed without the slightly raised profile to the edge of the central label area – called a “groove guard” – which is found on all later pressings. The first pressings of BNLP 1500-1557 all have a flat profile, and none after.
The flat edge also refers to the outer rim of the vinyl, where the straight cut edge is later followed by a rounded “beaded rim” This is a by-product of the waste extrusion trimming process immediately after pressing the vinylite biscuit.
2. Serrated Edge
Another “anomaly” found on a small number of Blue Note re-issues in the Liberty Years (1966-70) is the serrated edge, which was characteristic “trademark” of one pressing plant, believed to be Keel Mfg. Corp. of Hauppage, Long Island, N.Y. (long since defunct)
The significance of serrated edge is close to zero, however it is not “negative”. This pressing was pressed from an original Van Gelder Stereo master. I have five Division of Liberty pressings with serrated edge out of about fifty Liberty reissues. Uncommon, but not rare.
Liberty Serrated Edge:
1581 (re) Rollins/ Night at the Village Vanguard
84130 (re) John Patton/ Along Came John
84285 Three Sounds/ Coldwater Flats
84196 Hubbard/ Blue Spirits
84273 Mobley/High Voltage
Vinyl production process (wiki)