|  | 
| Keel's dead wax symbol (stamped on both sides) | 
Up to 
THE RIVER copies released early in the 1980s, most, if not all, of the U.S. vinyl copies of Springsteen's albums had been pressed at three major pressing plants of the U.S. Columbia Records: 
Pitman (ceased manufacturing vinyls in December 1986), 
Terre Haute (stopped vinyl pressing in late 1982), and 
Santa Maria (closed in 1981). As I wrote 
previously, however, the 
DARKNESS LP is the exception. This was because the 
Pitman pressing plant stopped operation temporarily due to labor issues just before the scheduled release date of his highly anticipated 4th album in Spring 1978. As a result, vinyl manufacturing factories, that had probably never made (or at least had not made major) contributions on pressing any of Springsteen's LPs before, got involved in the album production. This led to a small variety of the early vinyl copies of 
DARKNESS that differ in where they were pressed. In fact, the locations of pressing plants were mostly unusual for Springsteen's albums available back then, such as 
Pinckneyville, IL, and 
Scranton, PA. Such vinyl variants can be identified by checking label designs, circular indents on the labels, or matrix etchings and unique stamps found on the dead wax space.