6. Aluminate of potash. The caustic lye is prepared by boiling together
for an hour 100 gallons of water, 200 lbs. of potash, and 80 lbs. of
quicklime; the mixture is then allowed to settle, the supernatant liquor
is decanted, and evaporated till its density be 35° B. In 30 gallons of
that lye at a boiling heat, 100 lbs. of ground alum are to be dissolved.
On cooling, crystals of sulphate of potash separate. The clear liquor is
to be decanted off, and the crystals being washed with a little water,
this is to be added to the lye. About 33 gallons of mordant should be
obtained.
_Mordant for Black._
The pyrolignite of iron called iron liquor in this country, is the only
mordant used in calico-printing for black, violet, puce, and brown
colours. The acetate of alumina, prepared from pyrolignous acid, is much
used by the calico-printers under the name of red or yellow liquor,
being employed for these dyes.
We may observe that a strong mordant, like No. 2., does not keep so well
as one of mean density, such as No 1. Too much mordant relatively to the
demands of the works should therefore not be made at a time.
There are eight different styles of calico-printing, each requiring
different methods of manipulation, and peculiar processes.
1. The madder style, to which the best chintzes belong, in which the
mordants are applied to the white cloth with many precautions, and the
colours are afterwards brought up in the dye-bath. These constitute
permanent prints.
2. The padding or _plaquage_ style, in which the whole surface of the
calico is imbued with a mordant, upon which afterwards different
coloured figures may be raised, by the topical application of other
mordants joined to the action of the dye-bath.
3. The reserve style, where the white cloth is impressed with figures in
resist paste, and is afterwards subjected first to a cold dye, as the
indigo vat, and then to a hot dye-bath, with the effect of producing
white or coloured spots upon a blue ground.
4. The discharge or _rongeant_ style, in which thickened acidulous
matter either pure or mixed with mordants, is imprinted in certain
points upon the cloth, which is afterwards padded with a dark-coloured
mordant, and then dyed, with the effect of showing bright figures on a
darkish ground.
5. China blues; a style resembling blue stone-ware, which requires very
peculiar treatment.
6. The decolouring or _enlevage_ style; by the topical application of
chlorine or chromic acid to dyed goods. This is sometimes called a
discharge.
7. Steam colours; a style in which a mixture of dye extracts and
mordants are topically applied to calico, while the chemical reaction
which fixes the colours to the fibre is produced by steam.
8. Spirit colours; produced by a mixture of dye extracts, and solution
of tin, vulgarly called spirit by dyers. These colours are brilliant but
fugitive.
I. The madder style; called by some dip colours. The true chintz
patterns belong to it; they have from 5 to 7 colours, several of which
are grounded-in after the first dye has been given in the madder bath.
In dyeing with madder; sumach, fustic or quercitron, is sometimes added
to the bath, in order to produce a variety of tints with the various
mordants at one operation.
1. Suppose we wish to produce flowers or figures of any kind containing
red, purple, and black colours, we may apply the three mordants at once,
by the three-colour cylinder machine, putting into the first trough
acetate of alumina thickened; into the second, acetate of iron; and into
the third, a mixture of the two; then drying in the air for a few days
to fix the iron, dunging, and dyeing up in a bath of madder and sumach.
If we wish to procure the finest madder reds and pinks, besides the
purple and black, we must apply at first only the acetate of alumina of
two densities, by two cylinders, dry, dung, and dye up, in a madder
bath. The mordants of iron liquor for the black, and of iron liquor
mixed with the aluminous for purple, must be now grounded-in by blocks,
taking care to insert these mordants into their precise spots: the goods
being then dried with airing for several days, and next dunged, are dyed
up in a bath of madder and sumach. They must be afterwards cleared by
branning. See BRAN, DUNGING, and MADDER.
2. Suppose we wish to produce yellow with red, pink, purple and black;
in this case the second dye-bath should contain quercitron or fustic,
and the spots intended to be yellow should receive the acetate of
alumina mordant.
3. The mordant for a full red may be acetate of alumina, of spec. grav.
1·055 thickened with starch, and tinged with Brazil wood; that for a
pale red or pink, the same at spec. gravity 1·014, thickened with gum;
that for a middling red, the same at spec. gravity, 1·027, thickened
with British gum; and for distinction’s sake, it may be tinged yellow
with Persian berries. The mordant for black is a pyrolignous acetate of
iron, of specific gravity 1·04; for purple the same, diluted with six
times its volume of water; for chocolate, that iron liquor mixed with
acetate of alumina, in various proportions according to the shade
wanted. Sumach is mixed with the madder for all these colours except for
the purple. The quantity of madder required varies according to the body
of colour to be put upon the cloth, being from one pound per piece to
three or even four. The goods must be entered when the copper is cool,
be gradually heated during two or three hours, up to ebullition, and
sometimes boiled for a quarter of an hour; the pieces being all the
while turned with a wince from the one side of the copper to the other.
(See WINCE.) They are then washed and boiled in bran and water for ten
or fifteen minutes. When there is much white ground in the chintz, they
must be branned a second or even a third time, with alternate washing in
the dash-wheel. To complete the purification of the white, they are
spread upon the grass for a few days; or what is more expeditious, and
equally good if delicately managed, they are winced for a few minutes in
a weak solution of chloride of lime.
4. In the grounding-in for yellow, after madder reds, the aluminous
mordant being applied, &c., the piece is dyed, for about an hour, with
one pound of quercitron bark, the infusion being gradually heated to
150° or 160°, but not higher.
5. A yellow is sometimes applied in chintz work after the other colours
are dyed, by means of a decoction of Persian berries mixed with the
aluminous mordant, thickened with flour or gum, and printed-on with the
block; the piece, when dry, is passed through a weak carbonated alkaline
water, or lime water, then washed and dried for the market.
6. _Black mordant._--Take half a gallon of acetate of iron, of spec.
grav. 1·04, 4 ounces of starch, and 4 ounces of flour. The starch must
first be moistened with the acetate, then the flour must be added, the
rest of the acetate well mixed with both, and the whole made to boil
over a brisk fire for five minutes, stirring meanwhile to prevent
adhesion to the bottom of the pot. The colour must be poured into an
earthen pipkin, and well mixed with half an ounce of gallipoli oil. In
general, all the mordants, thickened with starch and flour, must be
boiled, for a few minutes. With British gum or common gum, they must be
heated to 160° F., or thereby, for the purpose merely of dissolving
them. The latter should be passed through a sieve to separate the
impurities often present in common gum.
7. _Puce mordant._--Take a quart of acetate of alumina and acetate of
iron, each of spec. grav. 1·04, mixed and thickened like the black, No.
6. To give the puce a reddish tinge, the acetate of alumina should have
a specific gravity of 1·048, and the iron liquor only 1·007.
Red mordants are thickened with British gum, and are sufficiently
coloured with the addition of any tingeing decoction.
8. _Violet mordants._--These consist either of a very weak solution of
acetate of iron, of spec. gravity 1·007, for example; or of a little of
the stronger acetate of 1·04, mixed with acetate of alumina, and a
little acetate of copper, thickened with starch or British gum. The
shades may be indefinitely varied by varying the proportions of the
acetates.
When black is one of the colours wanted, its mordant is very commonly
printed-on first, and the goods are then hung upon poles in the
drying-room, where they are aired for a few days, in order to fix the
iron by its peroxidizement; the mordants for red, violet, &c., are then
grounded in, and the pieces are dyed up, after dunging and washing, in
the madder bath, into which, for certain shades, sumach, galls, or
fustic, is added. The goods are brightened with a boil in soap water;
occasionally also in a bath, containing a small quantity of solution of
tin or common salt. The following mode of brightening is much extolled
by the French, who are famous for their reds and roses.
1. A soap boil of forty minutes, at the rate of 1 pound for every 2
pieces. Rinse in clear water.
2. Pass through chloride of soda solution of such strength that two
parts of it decolour one part of Gay Lussac’s test liquor. See CHLORIDE
OF LIME and INDIGO. Wince the pieces through it for 40 minutes. Rinse
again.