Engraving of signature on glass is to be seen approx. 1940 and
proceeds to the end of 1980s and start of the 1990s, after that
signature is beginning to be done by laser technique.
It is my impression that engravings of signature on production
subjects has been random done as to how many items of the
production that did receive a signature, did depend very much on
how much spare time employees to do this quit time consuming
In the end of the 1980s it seems that signature to items is quit
less in numbers than you will find in the 1960s and the 1970s,
perhaps that is due to that there still was quit a few cutters
and engravers employed yet.
Unique (one of a kind) items, test items (mostly 2-9 items) was
all engraved with signature often done bye the glassblower, an
employee a skilled engraver or even the designer self.