Reference Book
Numbering
The process of imprinting tickets, cheques, certificates, or other items with
consecutive figures numbers and letters is called numbering. Using a device
called numbering machine, the figures are transferred from an inked relief
image onto the stock. Often numbering is set to start from the maximum amount
and run in the reverse order, so the last figure printed will be 1. This prevents
an over run and places the tickets, forms or other numbered material in correct
order.
Perforation
Perforation is an operation
that places a series of small
cuts or slits in the substrates
using various types of
blades or wheels on the
press or folder. Whenever
it is necessary to remove a
portion of printed material,
the sheet is perforated. This
makes it possible to readily
tear off and remove a reply
card on an advertising
circular or a page from a
book.
Varnishing
Varishing is a process that places a coating, or surface finish, on printed sheets
to impart resistance to chemicals, heat, water and other elements that would
otherwise damage the paper. Varnish can be applied over an entire press sheet
or on selective areas as a clear ink. An image printed in a dull varnish over a
gloss sheet is visible, due to the difference in reflection. A water based clear
and fast drying material called aquous coating is replacing other types of
varnishes. Aquous coating is available in both matte and gloss finishes.
Lamination
It is a process in which a thin film of plastic with an adhesive coating is bonded
to a printed substrate to provide protection against abrasion and moisture. A
common application of lamination is on restaurant menu cards which must be
protected from moisture and constant handling.
Liquid lamination is a coating method similar to varnishing. The plastic material
is applied in liquid form and then cured into a tough protective layer by exposure
to uv-light. For this reson it is sometimes calledUV-cured coating.