Stamps of half cent denominations were withdrawn in 1971 and the same year,
the inland postage rate for first class mail was raised from three to four
cents. This produced increased demand for the four cent stamp, while large
stocks of 2½ cent stamps remained (previously the rate for second
class mail was 2½ cents and this had increased to 3 cents). Many
sheets of the stamps both imperforated and perforated were sitting at the
printer in England, while others sat in Post Offices around the
country.
To handle the three different cases required three
different processes, which resulted in three varieties:
The
imperforate sheets were surcharged in England by photogravure (recess
printing) after which they were perforated and cut into sheets in the usual
way. This stamp has two thin horizontal bars and can be distinguished from
the other two varieties by the high quality of the photogravure printing
process and the screen dots which give the diagonal portion of the 4 a
stepped or almost digitised effect under a magnifying glass (
177a1 - left-most in the
photos).
The stamps that had already been perforated at the printers
could not be surcharged with photogravure as the gripping edges had already
been trimmed so they had to be surcharged by letterpress (surface
printing). This stamp is the most easily identified as the horizontal bars
are thicker and fairly poorly printed. (
177a2 - middle in both photos)
The
stamps distributed around Post Offices were returned to the New Zealand
Government Printer and surcharged locally by letterpress. The local print
stamp also has two thin horizontal bars but can be distinguished from the
recess printed stamp by the poor quality of the letterpress printing
process. (
177a3 - right-most in both
photos)
