This pane was printed by The House of Questa Limited,
one of the printers that used lithography to produce Machins until last year. The earliest low
value Machins were all produced by Harrison and Sons using photogravure. In the late 1970s,
the demand for stamps was so great that Royal Mail required additional printers. John Waddington
Security Print and The House of Questa both began producing Machins using lithography.
The first lithographed stamps were much less attractive than the photogravure ones.
As explained on the prior page, lithography is a planographic
process which produces a flat image. The enlargement of the lithographic plate shown above
reveals that lithography creates shading by varying the size of the dots that compose the
image, rather than by varying the depth as in photogravure. The resulting lithographed stamps were
muddy and lifeless, lacking both depth and contrast.
Some improvement was gained by using two, three, and even four different plates to produce
the monochrome Machins. The plates applied different shades of ink, providing contrast as well
as some depth. Towards the end of the 1980s, the quality of lithographed stamps had improved
so they nearly equaled the photogravure ones.
Then in 1997 photogravure leapt ahead with the new computerized process (which is now called “gravure”)
described on page 4. Royal Mail specified that all low value Machins
were to be produced by gravure with the exception of small print runs (such as booklet panes
with attached labels) for which the production of a gravure cylinder would be uneconomical. |
