[Illustration: CYLINDER PRINTING MACHINE.]
The trade of the Calico Printer may be said to be one of the most
important in this country, since we export such immense quantities of
cotton prints to our various colonies, as well as to other countries in
the world, that this business forms a very considerable part of British
commerce.
Calicoes, muslins, &c. intended for printing must first have the fibres
removed from their surface by the operation of the singeing machine;
which consists of a half-cylinder of iron or copper laid horizontally,
and kept at a bright heat by a range of gas-flames or a furnace; over
this half-cylinder the length of cloth is drawn with a steady motion till
the down or fibre is singed off.
[Illustration: Bowking Kiers.]
The next process is that of bleaching, because the whiter the cotton
cloth becomes, the more light it will reflect from the surface, and the
more brilliant the colour of the dyes will appear.
The principal chemical substance used for bleaching cotton is chloride of
lime, which is known as bleaching powder; but there are several processes
employed in its application, as well as various methods which are
adopted by different manufacturers to increase its effects by mechanical
contrivances, the application of heat, or otherwise.
[Illustration: Dash Wheel.]
The first operation of bleaching, however, and that which immediately
follows singeing, is boiling the cloth in an alkaline bath consisting
of a solution of soda. For this purpose a _bowking apparatus_ is used.
This machine (_see cut_) is, in fact, a large cauldron, with a flat false
bottom to protect the cloth from being scorched by the fire beneath.
Through the centre of this false bottom a vertical pipe rises from near
the real bottom to a height above the top of the cauldron, and carries a
conical cap like an umbrella above its open end at top. When the liquid
in the cauldron begins to boil thoroughly the steam forces a constant
stream of liquid up the pipe, which stream is scattered by forcing
against the umbrella-shaped cap, and so falls with some force back on to
the cotton in the cauldron. When this process has continued long enough,
the liquor is allowed to cool, and the cotton is taken to be rinsed at
the _dash wheel_, where it is subjected to the free action of water, or
to a rinsing machine, so constructed that the web travels on rollers, and
is thoroughly washed during its course.
[Illustration: Wringing Machine.]
The simplest and earliest method of imprinting figures upon calico is
by means of a wooden block, upon the face of which the design is cut in
relief, as in an ordinary wood-cut. The block is of sycamore, holly, or
pear-tree wood, or more commonly of deal, faced with one of these woods.
The block varies in size from nine to twelve inches long, and from four
to seven inches broad, and it is furnished on the back with a strong
handle. When the design is complicated, and a very distinct impression is
required, the figure is sometimes formed by the insertion of narrow slips
of flattened copper wire, the space between being filled with felt.
[Illustration: Face of Block for Calico Printing. Back of Calico Block.]
The printing block, which is worked by hand, is charged with colour by
pressing it gently upon a piece of superfine woollen cloth called the
_sieve_, stretched tightly over a wooden drum, which floats in a tub full
of size or thick varnish to give it elasticity, so that every part of the
raised device may acquire a sufficient coating of colour. The sieve is
kept uniformly covered with the colouring matter by a boy or girl called
the tearer, who takes up with a brush a small quantity of the colour
contained in a small pot, and distributes it uniformly over the surface;
for if this were not done, the block would take up the colour unequally.
The printing shop is a long well-lighted apartment, the air of which
is kept warm for the purpose of drying the cloth as it is printed; to
insure which it is passed over hanging rollers, so as to expose a large
surface to the air. The printing table, which is about six feet long, is
made of some well seasoned hard wood, such as mahogany, or of marble, or
flag-stone, the object being to present a perfectly flat hard surface.
This table is covered with a blanket, upon which the calico is extended,
and the block, being charged with colour, is applied to its surface, a
blow being given with a wooden mallet to transfer the impression fully
to the cloth. It is necessary, of course, to join the different parts
of the design with precision, and in doing so the printer is guided by
small pins at the corners of the block. Thus, by repeated applications of
the block to the woollen cloth and to the calico alternately, the whole
length of calico is printed.
[Illustration: Drying Room.]
By this method, a single block prints only one colour, so that, if
the design contain three or more colours, three or more blocks will be
required, all of equal size, the raised parts in each corresponding
with the depressed parts in all the others; in order, therefore, to
print a piece of cloth twenty-eight yards long, and thirty inches broad,
with three blocks, each measuring nine inches by five, no less than
672 applications of each, or 2,016 applications of the three blocks,
are necessary. Thus it will be seen that printing by hand is a tedious
operation, requiring more diligence than skill.
[Illustration: Brush.]
When the design, however, consists of straight parallel stripes of
different colours, they may be applied by one block at a single
impression. For this purpose the colours are contained in as many small
tin troughs as there are colours to be printed. These troughs are
arranged in a line, and a small portion of each colour is transferred
from them to the woollen cloth by a kind of wire-brush. The colour is
distributed evenly in stripes over the surface of the sieve by a wooden
roller covered with woollen cloth. For the rainbow style, as a peculiar
pattern is called, the colours are blended into one another at their
edges by a brush or rubber.
An important improvement has been made in the construction of
hand-blocks, by the application of a stereotype plate as the printing
surface. A small mould is produced from a model of the pattern, and the
stereotype copies are then made by pouring mixed metal into it. A number
of the stereotype plates are then formed into a printing block, by being
arranged in a stout piece of wood.
[Illustration: One of the Cylinders of the Machine, showing the way by
which it is coloured.]
The greatest mechanical improvement in the art of calico printing was the
invention of the _cylinder_ or _roller_ printing at the end of the last
century. This style of printing has been generally adopted in Lancashire,
and is the cause of the success of the English over the continental
printers. One cylinder machine, attended by one man to regulate the
rollers, is capable of printing as many pieces as one hundred men and
one hundred girls could print with hand blocks in the same time. A mile
length of calico can be printed off with four different colours in a
single hour.
This cylinder machine consists of a hollow cylinder or roller of copper,
about three feet long and three or four inches in diameter, the pattern
on which has been produced by the pressure of a mill, on which the design
has been originally stamped by the pressure of a hard steel roller which
has been engraved.
The copper cylinders are mounted on a strong iron shaft with a toothed
wheel at its end, in order to put it in train with the rotatory printing
machine for one, two, or more colours. On a roller at the upper part of
this apparatus are wound the calico webs stitched together, the end of
which is brought between the engraved copper cylinder and a large centre
roller covered with blankets, against which it is made to bear with a
regular pressure.
The engraved cylinder turns on the top of another cylinder covered with
woollen cloth, which revolves at the same time as the former, while its
under part dips in an oblong trough containing the dyeing matter, which
is of a pasty consistence. The engraved cylinder is in this way supplied
with plenty of printing colour, and is cleared from the superfluity by
the thin edge of a blade made of bronze, called the _doctor_, which is
applied to it as it turns, and gently scrapes the surface. After this
the cylinder acts upon the calico, which receives the impression of the
pattern in colour, and rolls onward at a great rate of speed.
There are various kinds of colours or dye stuffs used in calico printing,
some of which impart fast colours by themselves, and others which require
the web to be first prepared in order that they may become fixed.
In almost all the modes of calico printing the processes are very
numerous to ensure the beauty and permanence of the colours. In what
is called the _steam colour_ printing, the agency of steam is applied
to aid in fixing the colours to the cloth. The cloth is first steeped
in a mordant or fixing liquor, then printed by the cylinder in various
colours, called steam colours. It is then hung up to dry, and is
afterwards exposed to the action of steam by means of various apparatus,
which are adapted to the particular effect intended, to be produced in
fixing the dye.
The designs for calico printing are very expensive, and such a constant
succession of new patterns are demanded, that some of the Lancashire
printers expend several thousands a year on designing and engraving alone.
[Illustration]