From phillip holmes: "...if the deadwax info is the same on a supposed test
pressing as a WLP or first issue, it probably isn't a test pressing? ..."
I've never encountered the term deadwax before.
A test pressing would be identical to the first issue (assuming the press
run had been approved!) except for what was typically a reversed scrap label
which sometimes had ID information written on it. (I've occasionally seen a
plant use a special test pressing label but usually not.)
When they start a pressing run the first few will often be bad because the
press temperature hasn't stabilized. For this reason they might press ten,
throw out the first three because of non-fill, check one out with a
microscope, play it, put a couple on file and send the remaining four or
five to the client. If a client was smart, they'd file away at least one to
prove what they'd signed off on had been ok in the event of a bad pressing
The rest would be passed on for the producer and engineers to check. I would
be very surprised to see test pressings that weren't actually promo copies
turning up very often among collectors.
Bob Olhsson Audio Mastery, Nashville TN
Mastering, Audio for Picture, Mix Evaluation and Quality Control
Over 40 years making people sound better than they ever imagined!