Polskie Nagrania Muza

Polish state-owned label in the People's Republic times, still active these days (releasing mostly the old, remastered recordings, classical music, operas, etc.).
Currently the brand is owned by Polish branch of Warner Music.

Some useful information which could be helpful when establishing the year of release of LPs (up to year 1991) or at least the years range:
Prefix
SP - 7'' / 45 rpm mono single play
SS - same line as above, but in stereo (from mid 70's)
N - 7'' / 45 rpm mono EP
SN - same line as above, but in stereo (from mid 70's)

L - used for 10” / 33rpm longplays

for 12'' longplays:
XL - used for mono LPs – up to 1975/76
SXL - used for stereo LPs – up to 1975/76
X - used for mono LPs (mainly reissues) – after 1975/1976
SX - used for stereo LPs (reissues and new releases) – after 1975/1976
In the transition period quite often there was a different prefix printed on the sleeve ( XL/SXL or SXL) and on the centre label (X or SX).

Matrix numbers
For early mono releases prefix XW was used for matrix number (printed on labels and etched on runouts).
When stereo records were introduced, there was M-3 XW for mono and S-3XW for stereo records printed on labels and respectively M3XW and S3XW etched on runouts. The number after the prefix had nothing in common with the catalogue number and was different for A and B side. Etched matrix number could be followed by dash and a digit for represses. Next, after a space, a combination of letters was etched (for example MJ-KW).
After 1975/1976 matrix numbers were not printed on labels just stamped on runouts and they had M3X prefix for mono and S3X for stereo version which was followed by the catalogue number and then A for A side and B for B side, and alternatively dash and one or two digits for repress. After a long space a letter (usually C, J or K) was stamped.
In the transition period there were releases (mainly reissues or represses) with older matrix number printed on labels and new matrix number stamped on runouts, sometimes there was the old matrix etched on one side whilst on another side the new matrix was stamped.

Logo
From 1956 to 1967/68 there was non-framed logo with rooster and words Polskie Nagrania and MUZA printed on sleeves (see image).
Then there was similar logo but oval-framed printed on sleeves (see ).In about 1971 a newer version of oval logo appeared, with different font of writings: POLSKIE NAGRANIA and Muza (see ).In 1979/80 a new – rectangular, also called as “clef”, logo was introduced, initially printed only on sleeves (see ). In 1984/85 a new design of centre labels was introduced: with above mentioned new, clef logo (in place of previous big word “Muza”) and ZAIKS as Rights Society (in place of previous BIEM). (Compare for example: () to (). These new labels were mostly cream, could differ in shades. Some submitters insists there were also white labels (very rarely).