The Express.
London, England, 1861-07-12 00:00:00

LONDON, FRIDAY EVENING, JULY 12, 1861

ELECTRO PRINTING BLOCKS.

We have received from the office of the Electro 1
Printing Block Company a roll of maps, prints, show cards,
and other eograviep, forwarded as specimen products of the
remarkable invention which they have placed at the service
of the public. In the patented printing process which they
employ the surface which receives the ink is a sheet of rid-
mused indiarubber, and upon the elasticity of this sub-
stance the economy of expense, which is one of its chief re-
commeadations, depends. There is a large class of printed
works which are required to he produced on various scales,
and the process of the Electro Printing Block Company is
one for producing them all from a single engraving. The
sheet of indiarubber is first prepared to take litho-
graphic ink, it is then fixed in a steel frame capable of
expanding it equally in all directions. On this prepared
surface lines are drawn at right angles ; these are for the
purpose of measurement only. The picture to be enlarged
is now printed upon its face in the usual way, and supposing
it is to be amplified fourfold, the screw frame-work is
stretched until one of the squares formed by the intersec-
tion of the lines measures exactly four times the size it did
whilst in • state of rest. It is now lifted on to a litho-
graphic stone, and printed, and from this impression copies
are worked off in the usual manner. If the picture has to
be worked with type, the enlarged impression has of course
to be made from block plates, the printing lines of which
stand up like those of a woodcut. This is accomplished by
printing the picture with prepared ink, upon • metal plate ;
the plate is then subjected to voltaic ashes, which este
away the metal excepting these parts protected by the ink.
It will be apparent that this process is capable of inversion,
that the large engraving may be produced first by making
the drawing on • sheet already expanded, and that when
allowed to contract to the size required it will be available
for smaller prints. We have before us a hand•map of Bed-
fordshire, and by its side an enlargement of library atlas size,
both from the same original drawing, and we are informed
that a wall map may be produced from it in • very short
time. We have another map which has been enlarged from
• steel plate at • cost of about two guineas, being about
eight-and-twenty pounds less than by the old process. It
may be reasonably assumed that bad this prxess been in-
vented when the publication of the maps of the Ordnance
Survey was resolved on we should have had the country
mapped on a much larger scale, since the smaller
scales, for general use, could have been produced
with perfect accuracy from the larger one at trifling
cost. In the same way pictures may be printed
of various sizes without the expense of repeated en-
gravings. And not only pictures, but types may be re-
produced with variations of size. A printed page of royal
octavo may be brought down to • demy octavo, or very much
smaller, with a saving in the cost of a Bible of more than
9001., and a certainty of getting • fac simile. The
powers of this invention, and their adaptability to every
kind of work hitherto performed by typography and en•
paved plates, seem to promise an enormous multiplication
and diffusion of works of art and literature as 110011 as they
become generally known.