COLOUR PRINTING: By H. C.
N the general run of commercial three and four-colour printing, the
printer who lacks experience in all its details should make haste slowly.
It is better to be extremely careful on the first colour of the production
than to be full of care when the job reaches the final stage.
That the press should be in a fit state to give perfect register must
be patent to the veriest novice. Also, it is not an atom of use proceeding
with the making ready until this most important detail has been fully de-
monstrated to be absolutely perfect.
Various methods may be adopted to gain this end. A full-sized forme
interspersed with hair-line rules is a simple test. The most perfect method,
however, is to put on a good-sized forme of process blocks and carefully
make ready, putting up exactly the number of sheets required to ensure
the cylinder travelling at the same rate as the carriage of the press. This
being correct, run off at least one hundred sheets of good matured art paper.
The sheets should be run through the press at least three or four times, and
be closely inspected with a good glass after each impression. Should there
be the slightest indication of the press not registering this will be easily
demonstrated to even the inexperienced workman by the screen-Work
showing a blurred or doubling appearance.
With a comparatively new press it may be possible for the operator to
remedy any slight defect that may be apparent with very little trouble,
providing his mechanical knowledge is above the average. It is better,
however, in most instances, to call in the services of a practical engineer.
I might here state that the larger the circumference of the impression
cylinder the easier the making ready will be for the operator. A cleaner
impression and better finished appearance of the job is a certitude. There is
less drag on the sheet running through under the larger circumference than
on the smaller cylinder, provided there is sullicient weight of metal in the
framework and cylinder to stand the strain of heavy pressure required on
a full sheet of plates.
With all mechanical details passed as correct, the workman may proceed
with the job in hand.
We will take a double crown sheet of three-colour blocks, eight down.
They should be mounted either on solid metal or on a good iron-clamped
board.
Practical opinions differ very slightly as to the utility of each. In the
writer's opinion the solid metal mount is absolutely unsurpassable in the
hands of a practical man. The novice may find the wooden mount slightly
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