Modern advertising would not have been possible without photo-engraving.
Attention has been attracted, desire has been created and goods have
been sold, largely through the pictorial or other artistic
embellishments which have lifted particular “ads” out of the mass and
attracted the favorable attention of the cursory reader. Pictures are
the universal language, not only to those of divers tongues, but to
those of every stage of mental development.
Photo-engravings are a comparatively modern product. They superseded
wood engravings, which for years has been the recognized medium for
illustrations to print on a type printing press. Photo-engravings,
broadly speaking, are divided into two classes--line engravings and
halftones. The distinction between them lying in the fact that one, as
its name implies, is a reproduction of a drawing made in lines or
stipples, while the other, the halftone, gets its name from the method
of its manufacture.
Briefly stated, the process of making halftones is as follows: The
subject to be engraved is photographed through a halftone screen,
so-called. This halftone screen is a glass plate ruled with lines at
right angles ranging, for different purposes, from 60 to 200 lines to
the inch. This screen is placed between the lens and the sensitized
plate which is to be the negative. The necessity for this screen is due
to the fact that a photograph is made up of “tones.” That is to say,
that the color changes imperceptibly in subtle gradations of light and
shade. If this copy were photographed on a piece of copper it would
present no chance for the etching fluid to act. The idea is to break up
the surface into various sized dots, as the various gradations of color
on the original cannot be transferred by any other method to a sheet of
copper and etched.
[Illustration: HALFTONE ENGRAVING]
The various tones must be changed either to lines or dots, so as to make
a printing surface for the ink roller of the press to operate. This is
necessary to get the desired printing surface.
The dots are of various sizes, ranging from a minute stipple to a solid
black, and they present to the eye the same effect as the unbroken tones
of a photograph. The negative when finished shows the drawing exactly
like the original. The whites are opaque, the solid blacks are clear
glass, the intermediate tones showing the same values in stipples of
various sizes. The film of the negative is next removed from the glass,
turned and placed on a heavier plate glass with a number of others and
printed on a sheet of metal which has been coated with a sensitized
solution.
This plate of heavy glass containing the several negatives is placed
with the sensitized metal in a printing frame. The light passes through
the clear part of the negative, the solid parts prevent the passage of
light; thus we have the light acting chemically on the sensitized
surface.
After the print is removed from the printing frame, it is developed, the
parts acted on by the light adhering to the metal. The opaque parts,
through which no light has penetrated, leave the solution soft on the
surface of the metal. This is removed by placing in water and wiping
gently with absorbent cotton. The print is then dried and heated over a
stove which bakes the sensitized solution to the metal. It can readily
be seen that this sheet of metal is now in such shape that the etching
fluid will etch away the uncovered portions of the metal and allow the
protected parts, which represent the color of the original, to remain in
relief.
[Illustration: LINE ENGRAVING]
This plate is etched--a flat proof, so called, is pulled on a hand
press--and it is then taken up by the re-etcher. The re-etcher is the
artist of the etching room. He takes the plate and by covering up
certain parts and etching again gives additional play of color. Smaller
developments of lights are worked out by careful manipulation of the
etching fluid with small sable brushes. The differences in cost in the
production of halftones is due largely to the length of time devoted to
this work. The engraver or finisher then takes charge of it, preparing
the engraving for the routing department, where the superfluous metal is
removed. The plate is then returned to the engraving department, which
completes the work, burnishing darks, engraving highlights, removing
slight imperfections and otherwise perfecting the plate.
It is then proofed and blocked. Nine separate men handle each engraving
in the halftone department.
The making of line engravings follows the same general course, with the
exception that no halftone screen is needed, the copy to be reproduced
being already made up of lines or dots or a combination of them. In the
handling of line work, eight skilled men successively handle each plate.
[Illustration: COMBINATION ENGRAVING]
In addition to plates made by either line or halftone process,
combinations of the two are frequently used, as, for instance, where
decorative pen work is used to embellish a halftone picture, or where
lettering is to be used in connection with a halftone and form part of
the same plate. These plates made up of both line work and halftones are
known as combination plates or double-prints, depending upon the way
they are produced. In both cases, negatives are made of both the
halftone and fine copies.
Combination plates are made by combining the halftone and line negatives
together and making one complete print on the metal.
Double-print is used where the surface is covered with halftone screen,
either the line or halftone negative is printed on the metal, the other
is superimposed on it.
The Benday process, so called, is the use of mechanical appliances for
adding lines or stipples to either drawings or plates. Its use is very
extensive in the making of tint blocks or color work, used either in
connection with line or halftone key plates.
The highlight process, possible only with certain kinds of copy, is a
modification of the halftone in which, by manipulation of the time of
exposure and the screen when making the negative, the halftone stipples
are lost and in this way halftones are produced in which there are pure
whites, without the necessity of the finisher cutting them by hand.
[Illustration: BENDAY ENGRAVING]
Color Engravings.
Let us assume that we have a painting or a drawing in colors from which
it is desired to produce a set of printing plates to produce that
drawing in facsimile. Under the old method of procedure, lithography, it
would have been necessary to make a stone for each of the colors, which
would mean, roughly speaking, from twelve to eighteen stones to
reproduce it--it will be understood that this means the finished print
must go through the press once for each color. This would mean twelve to
eighteen impressions to get the desired result. The expense of doing
this limited the use of lithography.
[Illustration: HIGHLIGHT ENGRAVING]
The modern or photo-engraving method of reproducing a colored copy is
based on the theory of the three primary colors, yellow, red and blue.
It is assumed that every color is formed by some combination of these
three colors--the problem confronting us, therefore, is to separate
these three colors and if possible make a printing plate of each color
with the color values varying from light to dark in such proportions
that when the three are printed in proper register over each other, with
transparent printing inks, the varying color values will blend so as to
reproduce the original. We go about this by making three negatives, one
of each color, the red negative is made by placing at the lens a
so-called color filter, which separates the red rays, whether they
appear as pure red or any part of an orange or a purple, or any of the
many tones of which red may form a part. In like manner the yellow and
blue plates are made by the use of appropriate color filters, each of
which acts for its required color as that used for the red.
So far this would appear to be a purely mechanical operation, requiring
simply the usual care in negative making, but unfortunately this theory
does not work out so absolutely in practice, and for this reason, while
any color may be produced in light rays by the union of the three
primary colors of the proper quality, when the operation is attempted
with material pigments or ink, produce results varying widely from the
ideal. No pigment is absolutely pure, the adulterants or foreign
substances will cause sufficient deviation from the abstract standard to
cause a very noticeable difference in the finished result when united
with another color which is of itself impure. The result is that the
three negatives, instead of each being a true unit, ready for
combination with the others, is really only a basis for further work. It
might justly be compared with a sketch which is all right as far as it
goes, but which requires toning down and elaboration before becoming a
finished work of art.
The three negatives are each printed on sensitized copper, as was noted
with the black and white halftone; they are then turned over to the
re-etcher, who may be rightly termed an “artist-etcher.” He has before
him three prints on copper; on each of them are tones which to his
trained eye are too light or too dark to produce the desired result when
printed with the other two, which also vary more or less. It is his duty
to strengthen and reduce and otherwise manipulate the plates so that
they will, when finally printed, have the desired result.
For every particular use to which an engraving can be put, there is some
particular style or grade of engraving better adapted than any other.
The successful use of halftones, whether in black and white or in
colors, depends on the care with which the particular screen is selected
to suit the paper stock and printing conditions. To illustrate this, the
150-line screen has 22,500 stipples to the square inch. It is apparent,
therefore, that only certain kinds of paper can be used for such
halftones, whereas a 60-line screen contains only 3,600 stipples to the
square inch, which permits its use on a newspaper stock.
The production of engravings is just as highly technical and scientific
and involves as much experience and judgment in their application as any
of the learned professions.
* * * * *
Where are Milk-Pails Filled from Trees?
In South America there are some trees known as “cow-trees” which, when
wounded, yield a rich, milky, nutritious juice in such abundance as to
render it an important article of food. This fluid resembles in
appearance and quality the milk of the cow.
The cow-tree is a member of the bread-fruit family, and is most common
in Venezuela, growing to the height of a hundred feet. The leaves are
leathery, about a foot long and three or four inches broad.
In British Guiana the name is given to another large, much-branched
tree, and there are also other varieties in Para and along the Rio
Negro, which is a tributary of the Amazon River.
How did the Wearing of a Crown Originate?
When we speak of a crown now we mean the head-dress worn by royal
personages as a badge of sovereignty, but it was formerly used to
include the wreaths or garlands worn by the ancients upon special
occasions.
Among the Greeks and Romans, crowns made of grass, flowers, twigs of
laurel, oak, olive and so forth, and later of gold, were made use of as
honors in athletic contests, as rewards for military valor, and at
feasts, funerals and so forth.
It is, however, with the eastern diadem rather than with the classic
corona that the crown, as a symbol of royalty, is connected; indeed, it
was only introduced as such a symbol by Alexander the Great, who
followed the Persian usage. Antony wore a crown in Egypt, and the Roman
emperors also wore crowns of various forms, from the plain golden fillet
to the radiated or rayed crown.
[Illustration: CROWNS
1. Crown of England. 2. Russian Crown. 3. French Crown. 4. Austrian
Crown. 5. Imperial Crown (Charlemagne’s).]
In modern states they were also of various forms until heralds devised a
regular series to mark the grades of rank from the imperial crown to the
baron’s coronet.
The English crown has been gradually built up from the plain circlet
with four trefoil heads worn by William the Conqueror. This form was
elaborated and jeweled, and finally arched in with jeweled bands
surmounted by the cross and scepter. As at present existing, the crown
of England is a gold circle, adorned with pearls and precious stones,
having alternately four Maltese crosses and four fleur-de-lis. From the
top of the crosses rise imperial arches, closing under a mound and
cross. The whole covers a crimson velvet cap with an ermine border.
The crown of Charlemagne, which is preserved in the imperial treasury of
Vienna, is composed of eight plates of gold, four large and four small,
connected by hinges. The large plates are studded with precious stones,
the front one being surmounted with a cross; the smaller ones, placed
alternately with these, are ornamented with enamels representing
Solomon, David, Hezekiah and Isaiah, and Christ seated between two
flaming seraphim.
The Austrian crown is a sort of cleft tiara, having in the middle a
semicircle of gold supporting a mound and cross; the tiara rests on a
circle with pendants like those of a miter.
The royal crown of France is a circle ornamented with eight
fleur-de-lis, from which rise as many quarter-circles closing under a
double fleur-de-lis. The triple crown of the popes is more commonly
called the tiara.
Why do Lobsters Change Colors?
Before a lobster is cooked he is green, that being the color of the
rocks around which he lives on the bottom of the ocean. However, as soon
as a lobster is placed in boiling water his shell changes from green to
red. This is due to a certain chemical substance contained in the shell
which acts in that way when boiled.
How do Fishes Swim?
The fish is entirely surrounded by water which exerts an equal pressure
on all sides. When the fish moves its tail, or makes any movement at
all, he moves in the water. Of course, by moving his tail from side to
side he propels himself forward and by bending his tail he goes in the
direction in which it is bent.