This picture shows the pages of the Book of Wonders being printed.
Thirty-two pages are printed on each side of a sheet of paper at
one time. A printing office is a busy place as can be seen from the
picture. As soon as the ink is dry on the printed sheets they are taken
to the bindery where they are folded and sewed ready to have the covers
put on.]
[Illustration: HOW THE BOOK OF WONDERS IS BOUND
When the printed sheets are received in the bindery they are fed into
a folding machine which is shown here. A sheet of 64 pages is folded
and cut and delivered in four sections of 16 pages each ready to be
gathered.]
[Illustration: Here we see a machine which takes the folded sections of
16 pages each, which are called “signatures,” and sorts them, dropping
them into compartments in order, so that each compartment finally
contains the printed matter for one book all arranged in the order
which it will be bound.]
Courtesy of the J. F. Tapley Co. New York.
[Illustration: SEWING THE PAGES OF THE BOOK OF WONDERS
Here we see the girls at work operating the sewing machines which sew
the sections together at the back side of the book.]
[Illustration: The men in this picture are making the backs of the
books round and preparing them for the putting on of covers.]
Courtesy of the J. F. Tapley Co., New York.
[Illustration: THE BOOK OF WONDERS IS READY TO READ
In this picture we see the “case makers” at work making the covers on
which the actual book is bound.]
[Illustration: The book is now “bound” by having the covers put on and
is ready for distribution.]
Courtesy of the J. F. Tapley Co., New York.
How Is Photo Engraving Done?
[Illustration: This cut shows a section of a photo-engraving screen
enlarged, illustrating the squares above-mentioned. In reality it would
take from 100 to 400 of these dots to make an inch, according to the
fineness of screen.]
~HOW THE PICTURES IN THIS BOOK ARE MADE~
The first step is the making of the halftone negative which differs
from an ordinary negative in being made up of different sized dots
instead of shades of gray. This result is obtained by photographing the
picture through a halftone screen consisting of two pieces of glass,
ruled with black lines and cemented together so the lines cross at
right angles and leave small squares of clear glass.
The effect of making the negative in this way is to represent the
different shades from black to white by large or small dots. Wet plate
photography is usually used in this process because the film is thinner
and more intensely black besides being cheaper than dry plates.
[Illustration:
New Process Engraving Co.
This cut shows a portion of a halftone cut enlarged so that the dots
can be seen very plainly.]
Having made the negative the next step is to make a printing plate
from it. To do this, a piece of metal, copper if the work is fine, and
zinc for coarser work, is coated with a solution which is sensative to
light, fish glue is commonly used to which is added a small amount of
ammonium bichromate. The metal being coated and dried, it is put in
a very strong frame with the negative and squeezed together so that
they are in perfect contact. A powerful light is now directed upon the
negative with the metal behind it, the result being that wherever the
light goes through the white spaces in the negative, the coating on the
metal is rendered insoluble. Where the dots on the negative are, the
light is unable to get at the coating so that when the metal is removed
from the frame and thoroughly washed this part of the coating washes
away, leaving the part which the light got at attached to the metal.
This is now heated until the enamel, as the coating is called, turns
dark brown and the picture can be easily seen.
The picture is now on the metal but it must be made to stand out in
relief before it can be used for printing from, so it is put in a bath
of acid which eats away that part of the metal left uncovered by the
washing away of the coating and this leaves the dots which make up
the picture standing up in relief. A roller covered with very thick
paste-like ink is now rolled over the picture, or cut as it is now
called, and when a piece of paper is pressed against the ink covered
cut each little dot leaves a mark of ink on the paper the total making
up the picture as we see it.
There are many more wonderful things connected with the making of cuts
such as the routing machine which has a tool that revolves so fast
that it turns around 300 times while the clock ticks once, and other
machines which cut hard metal as easily as you can cut a potato with a
knife.
Colored pictures are also made by the process outlined above. The
picture is photographed three times with a different colored piece of
glass in front of the lens, the result being three negatives, one of
which has all the blue, one all the red and the other all the yellow
in the picture. By making cuts from each negative and printing them
on top of one another in yellow, red, and blue, the original picture
is reproduced in all its colors. This is how all our pretty magazine
covers are made.