Last Updated: December 27, 2022
The groove-type found on a Blue Note record offers a useful indication of the probable date of manufacture, and can help confirm or discount the status of a particular copy being an “original pressing”.
All original Blue Note records manufactured by Plastylite before mid-1961 have a deep groove on both sides, The groove is a “trench” around the outer circumference of the label, caused by the metal dies which hold the metal stampers in place during the pressing of the vinyl.
In Autumn 1961, new dies were introduced at the Plastylite plant, whose residual mark was a single “step” or ridge. The old DG and new non-DG dies were functionally interchangeable and coexisted for some four years, until the last of the old deep groove dies finally became worn out and discarded, in late 1965. During the four years between 1961 and 1965, Blue Note pressings appeared with every combination of die types: both DG, both non-DG, and DG only one side or the other.
The two types of groove are illustrated below:
Deep Groove (DG) on Side One and no Deep Groove on Side Two.
Various collector theories have been offered – the use of old dies for re-pressings, new dies for new original pressings, -but recollections of a Plastylite press operator in the early 60s (Larry C) was that type of die was of no significance: he merely used whichever came to hand. There was no reason to use either type.
The first pressing run of each Blue note title is associated with a particular groove combination, noted by Fred Cohen in his Guide to Blue Note Original Pressings. That schedule was compiled by Cohen in conjunction with elite collectors with extensive first hand knowledge of Blue Note original pressings, through a lifetime of collecting.
The groove combination assigned to the first pressing run depends on pressing being carried out on one press, with one pair of stampers affixed, typically, pressed over a number of working days. This would be consistent with around 4,000 records pressed for the original Blue Note release (my own estimate for early ’60s titles). In the event that there was a cause to interrupt the first pressing, the identifying marks are hostage to change e.g. different stamper, different press, and change of stamper fixing dies could all confuse the “correct” initial release. There are a few cases open to doubt.
Date of recording, date of manufacture and date of release
A study of all session and release dates for all titles shows on average, there was a ten month gap between the original recording session date (recorded on the tape box) and the month of release (according to Schwann Catalogues) . For some titles it was as little as 4-6 weeks, most often it was about 3 months, not uncommonly 6 – 9 months, and some titles waited several years. It is likely that the pressing of vinyl (expensive item) was only a month or two prior to release, and the groove pattern reflects what was current at the time of release, and not at the date of recording or inferred from the catalogue number sequence. When the labels were printed to accompany the first release is another unknown. Label designs changed.
The best indicator of the date of manufacture (after 1962) is which of the nine patterns of inner sleeve the record was packed with. Before those dates, there is a degree of uncertainty.
Beware the DG hype
Because DG dies continued in use at Plastylite until 1965, there are anomalies where the original pressing is no deep groove, and a subsequent repressing appears with deep groove, merely by chance. Deep Groove is definitive only for releases before 1961, ad even then there were many repressings within the deep groove era.
Consult Fred Cohen’s book on identifying first pressings for specific details on all mono releases by Blue Note Records (note, Fred has changed his judgement on a few since publication).
The presence or absence of deep groove is not a guarantee of superior audio performance, which is impacted by many other factors. Early pressings with DG suffered more wear and tear over the years. Second and subsequent pressings by Plastylite possibly not DG still employed stampers derived from the same intermediate Van Gelder metalwork, and still sound distinctively “Blue Note”, and are often in better condition. However, sentiment still holds sway over many collectors: they want a piece of history, they want the original.
How vinyl records were made
To better understand the phenomenon of deep groove, see the LJC Slackers Guide to making records below and gain “Instant Expert” Status.
LJC ” Expert in Thirty Seconds” Slacker’s Guide to making records
In only 30 seconds, everything you need to know to become an authority, shaving 30 seconds off the previous instant expert record of the One Minute Manager
Step One – from music to stamper
Music is cut onto a master laquer by lathe. All that important information (catalogue number, master engineer signature) stamped or written is here on the runout area of the soft laquer. Mother/stamper positive/negative metal parts are created. The stamper central area is punched out. Printed paper labels are trimmed and center-punched ready for use.
Step Two – from stamper to finished record
Hot vinyl biscuit is sandwiched by labels, and mounted between a side A and side B stamper. Ensuring the labels were bone dry was critical at this point, as any moisture converts to steam during pressing. The press applies 100 tons pressure to the biscuit at a temperature near 200 C for 30 seconds, pressing the grooves from the stamper image into the vinyl. As the press lifts away from the newly pressed record (bottom right) you see the indentation left behind in the central label area by the metal dies holding the stampers in the press. Deep Groove, or not Deep Groove, this is where it all happened.
Congratulations.You are now a fully certified 30-second Vinyl Expert, saving nearly four minutes on watching the whole Discovery Channel You Tube.
Origins of Deep Groove
The deep groove has its origins in the pressing 78 r.p.m. records. The deep groove circle is just slightly smaller than the label of a 78, located within the label edge. As the recording and distribution medium switched from the breakable shellac 78 first to the 10″” and then 12″ unbreakable microgroove 33/1/3 LP, with its larger label, the deep groove was incorporated into the design of the new labels. Deep groove remained a feature during this period until pressing plants commissioning new presses to keep up with the expanding demand for vinyl records, phasing out the old presses, and with them, the older deep groove dies.
(Thanks to Cristian for the info on 78 rpm)
Other record labels and the Deep Groove
Deep groove impression is found on many other record labels such as Riverside and Contemporary pressed around this time. There is not as much documented about how these fit into the chronology of other pressing plant processes as there is for Blue Note and the Plastylite vinyl pressing plant. Eight different types of pressing die grooves from late Fifties to early sixties, ranging from Plastylite-like on Contemporary, to deep pudding bowl on Verve
An example of more PPM – pressing plant mayhem – is this interesting “anomaly” on the Prestige label (photo courtesy of Albert of Ohio) of Coltrane’s 1958 recording Black Pearls, first released by Prestige in August 1964. Stereo copies of the original pressing exist with different label designs, one with deep groove, another with no deep groove.
These differences are almost certainly attributed to the spread of manufacture to different plants, who may also have been tasked to print labels locally, hence variations in typesetting, pressing dies, even the use of “out of date” designs. Whilst Blue Note used just one plant, Plastylite (plus one known exception), it became common for some labels to press at two or three plant location, some times contracting pressing to independents for cost advantage.
Anyone with a more serious interest in the subject of pressing die indentations on record labels, I recommend to seek professional help. Or indeed amateur help, such as myself.