Czech record manufacturer, operating under this name between 1948 and 27 October 1999.
The company started manufacturing shellac records in 1948 (after nationalization of Ultraphon and ESTA), vinyl records in the Loděnice plant (founded 1951) in 1953, compact cassettes in 1972, CDs in 1988 and DVDs in 2001. Occasionally it also acted as a label in the 1990s.
Company renamed to “GZmedia, a.s.” on 27 October 1999, to “GZ Digital Media” on 17 January 2000, and to GZ Media on 1 January 2014. Label renamed to “GZ vydavatelství” (GZ Publishing).

LABEL

Catalog# schemes
L1 ####-# ###
L1 ####/P-# ### = promo
After dash:
1st additional #: 0 = postcard, 1 = LP, 2 = CD, 4 = MC, 5 = DVD
2nd additional #: musical genre
3rd additional #: 1 = analogue, 3 = digital
4th additional #: media quantity

MANUFACTURE

CD matrix scheme 1989–1999

GZ XY####
“X” = year of matrix manufacturing:
A=1989, B=1990, C=1991, D=1992, E=1993, F=1994, G=1995, H=1996, I=1997, J=1998, K=1999
"Y" = month of matrix manufacturing:
1-9=January-September, A=October, B=November, C=December
Glass mastering code: LD01

Note:
CD matrix was stored for 2 years, i.e. any represses in that time window will bear the same number.
If the original CD matrix became damaged, a new one was created with a new number.
Note that the CD matrix year codes “A”, “B”, “C“, etc. are using since 2014 by GZ Media.

Shellac matrix schemes ~1946–1963

######-ZZ = mono, 10" or 12", 78 RPM
###### = mono, 10" or 12", 78 RPM
“Z” = galvanoplasty (runout only)
Note: All 78 RPM “standard records” (standardní deska) manufactured in Loděnice since 1951 were made from Bakelite; to be added to Format free text field.

Vinyl matrix schemes ~1951–1962

XX ####/Z Z~~~
“XX” = format:
VM = mono, 12" LP, 33⅓ RPM (VM = “velké mikro” = big micro)
MM = mono, 10" LP, 33⅓ RPM (MM = “malé mikro” = small micro)
VST = stereo, 12" LP, 33⅓ RPM (VST = “velké stereo” = big stereo)
MST = stereo, 10" LP, 33⅓ RPM (MST = “malé stereo” = small stereo)
“Z” = galvanoplasty (runout only)
“~” = additional/optional galvanoplasty/stampers (runout only)

Additional matrix schemes
16/#### = mono, 10", 16⅔ RPM
45/#### = mono, 7" EP, 45 RPM
45/SP-#### = mono, 7" SP, 45 RPM
45/ST-## = stereo, 7", 45 RPM
FO ###/ƒƒƒ = flexi/post card, 45 RPM (# = audio matrix, ƒ = photo number)

Note: On early 1960s represses the printed matrix numbers on labels may have still followed the old schemes, while the stamped matrix numbers in runouts already matched the new schemes (see below). The basic numerals usually remained identical.

Vinyl matrix scheme ~1962–1994

PX ####/Z Z ~ ~
“P” = label prefix (except Supraphon = void)
“X” = format *) see below
“Z” = galvanoplasty (runout only)
“~” = additional/optional galvanoplasty/stampers (runout only)

Label prefixes 1967–1993
none = Supraphon
D = Discant
O = Opus
P = Panton
T = Ar(i)ston
M = non-specified label prefix, used until 1989 for foreign releases (e.g. Hungary, UK, GDR, Vietnam) and since 1990 used also for domestic small publishing labels.

Additional label prefixes 1990–1994
A = M-Art
AR = Apollo Records Comp
AT = Akcent
B = Bonton
C = Punc and Vydavatelství Porta
CA = Carmen (2)
CR = Československý Rozhlas
D = Šafrán
DT = Direkt Records
G = Globus International and Kartáč Records
H = Edice Čs. Hifiklubu
HR = Hurikán Records
I = Romart and Interunie
J = Best IA
K = AG Kult
L = Gramofonové Závody
MA = Mua Brno
MC = Mute Czechoslovakia
N = Punc and Carera
PB = Presston (2)
PM = Popron Music
PN = Popron
PP = Parma Productions
PR = P&R (2)
PT = Pronto (5)
R = Monitor (2)
RE = Reset (2)
RL = Rival (7)
S = Supraphon
T = Edit (2)
U = Tommü Records
UT = Union-T
V = Primus
VA = Music Vars
VK = Voko
W = Multisonic
X = 6P
Y = Agentura Orion
Z = Melantrich
ZC = Malarie Records and Papagájův Hlasatel Records
& = unknown meaning (runout only)

Additional matrix schemes
### = 4" (experimental format), 45 RPM or 33⅓ RPM

Note: Matrices with stamped runout scheme С##-#####/#-# (late 1970s and early 1980s, example: С90-24709/1-2) were manufactured in the USSR and should not be listed under Gramofonové Závody. They can be listed in BaOI section under “Matrix / Runout”, along with the printed base GZ matrix numbers on center labels.

Vinyl matrix scheme ~1992–1998

MTX ####/Z Z
“M” = verbatim, no particular meaning
“T” = country of origin of recording (T = tuzemská = domestic, Z = zahraniční = foreign)
“X” = format *) see below
“Z” = galvanoplasty

Vinyl matrix scheme ~1998–2004

AX #####/Z
“A” = verbatim, no particular meaning
“X” = format *) see below
”Z” = galvanoplasty

*) Vinyl format code 1962–present

A = mono, 12" LP, 33⅓ RPM
A/16 = mono, 12" LP, 16⅔ RPM
B = mono, 10" LP, 33⅓ RPM
B/16 = mono, 10" LP, 16⅔ RPM
C = mono, 7" EP, 45 RPM
C/33 = mono, 7" EP, 33⅓ RPM
D = mono, 7" SP, 45 RPM
E = stereo, 12" LP, 33⅓ RPM
E/45 = stereo, 12" LP, 45 RPM
ED = stereo, 12" LP, 33⅓ RPM (Digital Recording = Digitální nahrávka)
F = stereo, 10" LP, 33⅓ RPM
G = stereo, 7" EP, 45 RPM
G/33 = stereo, 7" EP, 33 RPM
H = stereo, 7" SP, 45 RPM
K = supralong mono, 12" LP, 33⅓ RPM
K/16 = supralong mono, 12" LP, 16⅔ RPM
L = supralong mono, 10" LP, 33⅓ RPM
L/16 = supralong mono, 10" LP, 16⅔ RPM
M (old usage) = supralong mono, 7"
M (present usage) = stereo, 12" (also LP), 45 RPM
N = stereo, 10", 45 RPM
O = stereo, 7", 33⅓ RPM
Q = quadraphonic, 12" LP, 33⅓ RPM
Q/45 = quadraphonic, 12" LP, 45 RPM
V = mono, 7" LP Special, 33⅓ RPM
X = stereo, 7" LP Special, 33⅓ RPM

“EP” = Extended Play
“SP” = Short Play (“krátký záznam”)

LCCN how-to

Vinyl: Only the basic “XX ####” string (or “MTX ####”, or “AX #####”) should be entered, without the galvanoplasty suffix.

CD: Only the basic “X#####” string should be entered, without the “GZ” prefix or any optional suffixes.
Glass mastering code: IFPI LD01 - When featured on the disc use Glass Mastered At role with the XY#### in LCCN.
Mould SID code: IFPI 5J** - When featured on the disc use Pressed By role in LCCN.
"Glass Mastered At & Pressed By" - If both SIDs are present on the CD, both roles can be entered in the LCCN.