WHAT IS OFFSET PRINTING?
Offset printing is a widely used
printing technique where the inked image is transferred (or "offset")
from a plate to a rubber blanket, then to the printing surface. When
used in combination with the lithographic process, which is based on
the repulsion of oil and water, the offset technique employs a flat
(Plano graphic) image carrier on which the image to be printed obtains
ink from ink rollers, while the non-printing area attracts a film of
water, keeping the non-printing areas ink-free.
Offset printing advantages
Advantages of offset printing compared to other printing methods
Consistent high image quality. Offset printing produces sharper and
cleaner images and type than letterpress printing because the rubber
blanket conforms to the texture of the printing surface.
Usability on a wide range of printing surfaces (including wood, cloth,
metal, leather, rough paper and plastic) in addition to smooth paper.
Quick and easy production of printing plates.
Longer printing plate life than on direct litho presses because there
is no direct contact between the plate and the printing surface.
A "right" reading (not reversed) printing plate that is easy to proof
read prior to printing.
Offset printing is the most common form of high volume commercial
printing, due to advantages in quality and efficiency in high volume
jobs. While modern digital "presses" (inkjet based) are getting closer
to the cost/benefit of offset for high quality work, they have not yet
been able to compete with the sheer volume of product that an offset
press can produce. Furthermore, many modern offset presses are using
computer to plate systems as opposed to the older computer to film
workflows, which further increases their quality.
Private or hobby presses, engaged in patient production of limited
editions of fine quality books, often use letterpress as well as
offset methods, some "purists" preferring the slightly embossed look
resulting from the direct impression of inked type upon fine paper.
These books are sometimes printed from hand-set foundry type
(individual pieces of movable, lead-alloy type). Flexography, a form
of letterpress, is still used in the printing of high-quality premium
labels, in ticket printing, and in envelope manufacturing/printing,
though is now no longer the dominant technology. In Europe, however,
in the last two decades flexography has become the dominant form of
printing in packaging due to lower quality expectations and the
significantly lower costs in comparison to other forms of printing.