ON DYEING COTTON.
_To dye cotton a Saxon or chemic blue—Sulphate of indigo—Saxon or
chemic green—To set a cold indigo vat—Another indigo vat—To dye cotton
a fast green with the cold indigo vat and weld—Another cold blue vat for
linen and cotton—Solution of indigo for penciling printed muslin,
&c.—To dye cotton a fast buff—To dye cotton pink._
We refer the reader to the preceding chapter for many observations
relative to _cotton_, with which, in order to understand correctly the
best method of dyeing this material, it is necessary that he should
become acquainted: indeed, the whole of that chapter ought to be well
studied by every one desirous of becoming an expert dyer.
_To dye cotton of a Saxon or chemic blue._
This is performed with the _sulphate of indigo_ thus:—put into a brown
stone glazed earthen pot four pounds of good sulphuric acid, add to it
twelve ounces of good indigo finely powdered, stirring the mixture very
quickly and frequently: break the lumps, if it should get lumpy before it
is thoroughly mixed, with a glass rod, or with a stick, the bark of which
has been taken off: if for wool or silk, the solution will be fit for use
in forty-eight hours, but if for cotton it will not be fit for use till
the acid is neutralized by an _alkali_. Some persons, however, use
_whiting_, but this precipitates and wastes the indigo; others use
magnesia, but this is expensive: some, again, use pure or caustic potash
prepared thus—take American pot or pearl-ash about seven pounds, put
some of it into a brown stone glazed jar, or rather an open pan; upon the
ashes put some quicklime recently burnt, and then alternately ashes and
lime, slacking the lime with water as it is put on the ashes; let the
whole stand together for about two hours: provide now another brown stone
earthen vessel with a hole in the bottom, of larger dimensions than the
other, put into this a piece of coarse linen to prevent the lime, the
impurities, or any foreign body from running through the hole, then upon
the bottom put some of the previously mixed lime and ashes, well
incorporated, and placed gently upon the linen so as to be sure of its
keeping its place and letting the liquor pass through clear. As the
mixture is put in add some water occasionally, so as to keep it just
covered, and leave room at the top for the swelling of the materials, as
the lime especially will increase in bulk. Water must fill the whole, and
cover the lime, &c. which will be known by the bubbles ceasing to rise.
When it has stood twelve or fourteen hours, water being occasionally
added as it is absorbed, some may be drawn out.
To determine whether the carbonic acid has entirely quitted the potash,
(and for which purpose the quicklime, having a greater affinity with the
carbonic acid than potash has, is specifically applied,) take some of the
fluid in a wine glass and drop a drop of sulphuric acid into it; if the
carbonic acid has entirely combined with the lime, the sulphuric acid
will enter the fluid in the glass quietly, and without any other
appearance than so much water; if you still doubt add more drops of the
sulphuric acid successively. If the carbonic acid has not entirely left
the potash when the sulphuric acid is dropped into the liquor, an
effervescence or fermentation will be seen in it. Whenever this is the
case the liquor must be returned to the mixture for a longer time, and,
if necessary, more lime be added.
When the liquor or ley is fit for use, all of it is to be drawn off, and
more water may be added and remain on the ingredients till it is wanted.
It is best to keep it close from the air, because as the air contains a
certain portion of carbonic acid, the liquor would in time absorb it, and
the ley, instead of containing caustic potash, would become a solution of
carbonate of potash, and consequently not answer the end designed.
To know when the _alkali_ of the mixture is exhausted, take a piece of
paper stained with the juice of the blue flowers of violets, or the
blossom of the mallow, which is thus prepared—pound the blossoms in a
glass mortar with a glass pestle, and squeeze the juice into a tea-cup,
then, with a small hair pencil, cover a sheet of white paper with the
juice, and dry it for use. All acids will turn it _red_, and all alkalies
will turn it _green_; and, therefore, as long as any of the alkali
remains in the liquor, the paper thus prepared will, when immersed in it,
be stained green.
The comparative strength of such solutions may also be ascertained thus:
take a wine-glass full of the liquor, drop into it a few drops of
sulphuric acid, stirring it with a glass rod or clean bit of
tobacco-pipe, and then apply a bit of test paper; if it appear green more
acid must be added and stirred again; apply the test paper a second time,
if it be still stained green, a few drops more of the acid must be added,
and thus continue till the colour of the paper is neither altered to
green nor red: the liquor will then be neither acid nor alkaline, but
contain a neutral salt consisting of a combination of the acid and the
alkali. By adding, however, a few more drops of the acid, this last will
be found predominant, and the test paper, being immersed in the liquor,
will be stained red.
By treating different leys in this manner, and counting the number of
drops necessary to neutralize each, the strongest ley will always be
found that which requires the greatest quantity of acid for the purpose.
Alkaline leys are also to be judged of by their weight compared with that
of water; a wine pint of water usually weighs about sixteen ounces
avoirdupoise; all alkaline leys are _heavier than water_, and the heavier
they are the more alkali they necessarily contain. A wine pint of some of
them will weigh more than seventeen ounces.
To return to the dyeing of cotton a chemic blue: (to which a knowledge of
these chemical processes, as well as of other processes in our work, is
essentially necessary,) take some of the blue liquid prepared with indigo
and sulphuric acid, as before directed, and put it into a vessel large
enough to hold two or three times as much as is intended to be put in, in
order that there may be room to stir it; add some of the potash, or
alkaline liquor, by degrees till, after several trials, the mixture
ceases to be sour; or, if you do not like to taste it, take a small slip
of cotton or muslin and dip it in, after having wetted it out in warm
water. If the acid be neutralized the cotton will be sound, if not it
will be tender _when dried_: if the acid predominates much the cotton
will be as rotten as tinder; when the cotton is perfectly strong and
sound after being dried, the liquid is in a proper state to dye both
cotton and muslin.
The goods to be dyed must first be wetted out and wrung, then work them
in the flat tub with water, with a little of this blue added, and well
stirred in proportion to the shade wanted. From half a pint to a pint of
the liquid blue is sufficient for two pieces of twenty-four or
twenty-eight yards each, if not of a very full pattern.
Blue, when dyed, should be dried in a cool stove, and if book-muslins,
framed; furniture should be stiffened, glazed, or calendered.
The preceding are essentially the same directions for preparing and
dyeing with the _chemic blue_ which were given in the first edition of
this work, and which we see no reason to alter. As, however, for _silk_
in particular, another method has been given in the late work of Mr.
M'KERNAN, we give his processes below.
_Sulphate of Indigo._
"Take one pound of the best flora indigo in very fine powder, put this
into a stone-ware or lead vessel, then add gradually three pounds of the
best sulphuric acid, specific gravity 1.800; mix well and stir often, and
in twenty-four hours the indigo will be dissolved. Adding three ounces of
sulphur to the acid, and heating it to 180°; then, when cooled to 100°,
pouring the acid off the sediment, and then adding to it the indigo, is
considered the best way of opening or dissolving the indigo. When the
indigo and acid have been mixed twenty-four hours, add three pints of
boiling water; stir often; when cold it will be fit for use."
_To neutralize the sulphate of indigo._
"Take six pounds of alum and dissolve it in two gallons of water at 120°,
when dissolved add, by degrees, five pounds of pearl-ashes until the acid
of the alum is neutralized and the alumine formed, then put the whole on
a piece of calico that has been hooked in a square frame, or tied over a
vessel; when the liquor has run off then add one gallon of boiling water
on the alumine and stir it up well. When the water has gone through the
calico; the alumine is fit for use. Then add a part of this alumine to
some of the sulphate of indigo until the acid is neutralized."
_Saxon or chemic_ GREEN.
The same blue vat will do for _green_; but it is best to make another by
putting only eight ounces of indigo instead of twelve to four pounds of
sulphuric acid. If the preparation has been made two or three months it
is the better, having been often stirred before it was neutralized with
the alkali.
Prepare a strong decoction[7] of old fustic, which should always be ready
at hand as a store, keeping plenty according to the work to be done,
including cotton, silk, and worsted goods.
Mix some of the chemic blue with the decoction of fustic in the following
manner: put into a tub six pails of soft clear water, to which add a pint
of the neutralized blue; and six pails of the decoction of fustic; stir
all well together. Some dyers add a little weak alum liquor till it just
tastes before they put in the blue; it should be but little, otherwise it
will precipitate the fustic. This mixture should stand two hours to
settle.
The muslin or calico, say two pieces of twenty-four yards each, should,
with the usual precautions, be passed through a strong decoction of old
fustic or turmeric as hot as the hand will bear. They are then to be
taken out and submitted to a quantity of the green mixture above,
described, in proportion to the fulness of the green required. When
finished, whether for the calenderer or glazer, they should be dried in a
moderately warm stove.
These two colours are very fugitive, especially upon _cotton goods_; but
sometimes the customer will not go to the price of the fast green or
blue, hereafter to be described.
_To set a cold indigo vat for cotton, &c._
Put three pounds of slacked lime, sifted, into six quarts or more of
boiling water; stir the mixture well for some time, and after it has
settled, draw off the clear liquid, to which add three pounds of sulphate
of iron, stirring it well till all is dissolved; let it settle till the
next day; have ready a deal cask, because one made of oak would blacken
and otherwise injure the dye, in consequence of the affinity between the
tannin, &c. of the oak and the sulphuric acid. Put into the cask
seventy-five gallons of water, to which add the mixture of lime and
sulphate of iron; take now three pounds of indigo, well ground and ready
at hand, dissolved in three pints of strong solution of potash, such as
was directed to be prepared for neutralizing the chemic blue. Put this
solution of indigo and potash into the tub with the water, lime, &c.;
after it is well stirred, and left to settle, it produces a deal of
froth; but the liquor takes a fine green colour, which turns to blue when
exposed to the air.
_Soda_ may be used instead of potash, if treated the same way. Soda, it
may be observed, forms the usual ley of the soap manufacturer; and
answers for _soap_ much better than potash, because its combinations do
not usually absorb moisture from the air: potash, and several of its
combinations, do so.
_Another indigo vat._
Take five hundred quarts of water; indigo seven or right pounds. The
boiler must be iron.
Boil the indigo with sixteen pounds of a liquor made with potash and
eight pounds of lime. After the lime and potash have been in contact, as
in all these instances they should be, from twelve to twenty-four hours,
to take away the carbonic acid from the potash, the clear liquor of this
mixture is what must be used. The indigo must be previously powdered, and
ground extremely fine in water before it is put into the alkaline liquor.
The mixture must now be added to the five hundred quarts of water, and
the whole boiled till the indigo rises to the surface like cream, and
till, in striking the bottom of the boiler with a stick, it is found to
contain no solid substance.
While the indigo is boiling, another eight pounds of lime must be slacked
in about twenty quarts of warm water; dissolve in this lime-water sixteen
pounds of sulphate of iron. The vat being half filled with water, the
solution of lime and sulphate of iron is to be put into it; the indigo
solution is now also to be added. The vat, being thus filled to within
about three or four inches of the edge, must be stirred two or three
times a day till it is fit for dyeing, which it will be in about
forty-eight hours, and sometimes sooner, according to the temperature of
the air, by which the completion of the process is more or less
accelerated.
When the strength of the vat is exhausted, it must be, of course,
replenished. If the liquor becomes black, it wants sulphate of iron; if
yellow, lime is required. When the indigo is far spent, more must be
added in the same manner as at first.
In this vat, as respects the blue dye, if it be for muslin, calico, &c.,
the form should be square, about two yards long, one yard to one and a
half wide, and from seven to eight feet deep; the pieces of cloth are to
be hooked into a frame.
Where much work is done, it will be necessary to have two or three such
vats, in order that they may be worked in succession: by stirring them
some hours previously to working, the weaker will do for the lighter
shades, the stronger for the fuller colours. If the vat is in proper
order, the goods always come out green, and turn blue in the air. This
should be ascertained by small patterns previously to working the whole.
When any goods are dyed in these vats, if not full enough at one dip,
they may be left a certain time, and then be dipped again, once or more,
as they appear to require it.
When they are blue enough, and fully aired, they must be taken from the
hooks, and well washed off in two or three fresh clean waters, or at a
wash wheel in a clear running stream. When perfectly clean, they are
ready for the calenderer or glazer.
_To dye cotton a_ FAST GREEN, _with the cold indigo vat and weld._
After dyeing muslin blue in the blue vat, weld must be boiled in the same
manner as for fast yellow. The quantity of weld to be used, must be
according to the fulness of the blue ground, and of what shade the green
is to be; a proportion of alum must also be used. The goods, after being
worked in the same manner by the selvage, must be washed off, and
stiffened, if for the glazer, but not if for dress, but be framed by the
muslin dresser.
_Another cold_ BLUE _vat for linen and cotton._
The indigo is to be powdered, and put into warm water with sulphate of
iron, in quantity twice the weight of the indigo, to which is also to be
added, the same weight of fresh-burnt lime. The water should be only
sufficient to mix it thick at first; keep it stirred; and, as it becomes
dissolved and green under the surface, increase the water, often stirring
and trying the mixture, by putting in a pattern between the stirrings, at
some hours distance, between each pattern, and increasing the water: in
twenty-four hours it will be fit for use.
_Solution of indigo for penciling printed muslin, &c._
To twenty-five gallons of water, add sixteen pounds of indigo, and thirty
pounds of carbonate of potash; when mixed, and placed over the fire, as
soon as the mixture begins to boil, add quicklime, by a little at a time,
to render the alkali caustic; then twelve pounds of red orpiment, and
boil till it will give a yellow colour to transparent glass.
This form is from _Haussman_. Were the author to make this solution of
indigo, he would first make the alkali caustic with lime, and then put
the clear liquor to the other materials.
Mr. _M'Kernan_ gives another form for _pencil blue_ with indigo: the
principal differences between which and the above, consist in adding
equal parts of brown sugar and _gum senegal_ to it, which, in regard to
the addition of the gum, is, we presume, a great improvement.
Dr. URE (_Notes to Berthollet_, vol. ii. page 437.) gives a similar form
from _Vitalis_, for _topical_ or _pencil blue_; but he adds, it was much
used formerly. Another blue, of less permanence but more brilliance, is
now preferred; it is made thus:—
Into an earthen pot four ounces of finely ground and sifted Prussian blue
are to be put. Over this must be slowly poured, stirring all the while,
sufficient muriatic acid to bring it to the consistence of syrup. The
mixture is to be stirred every hour for a day, and afterwards thickened
with from four to eight pots (of two _litres_ each; a litre _French_
contains about two wine pints;) of gum-water, according to the shade
wanted.
_To dye cotton a_ FAST BUFF.
Take a brown stone pan or pipkin, glazed. It must not be the common
glazed wares, because these are glazed with _lead_, and the acids will
dissolve the lead; if, therefore, such are used, the lead being
dissolved, will be mixed with the dyeing materials, and sometimes totally
spoil the dye. Stone-ware, if used with care, will bear the fire: such
ware is usually glazed with muriate of soda or common salt.
Having a proper vessel capable of holding from two quarts to a gallon,
fill it half-full of strong _nitric acid_, to which add, in small
quantities at a time, either _old horse-shoe nails_ from the farrier,
they being the purest iron, or the _cuttings of tin-plate_ from the
tin-man's, for this is also very pure iron, although covered with tin;
but the small portion of tin in the iron is not inimical to the dye. Be
careful not to put too much in at a time, nor to stoop near to it while
the solution is going on, as the red fumes arising are very noxious; and
if the iron be added in large quantity, so much effervescence would be
produced, that a considerable part of the liquor would be thrown over the
top of the vessel.
When this solution is prepared in haste the air is greatly contaminated,
and therefore it is best to prepare it long before it is wanted, and
slowly, by dropping hourly small quantities of the iron into the acid,
and then little if any perceptible fumes will arise. Continue this
process till, by stirring with a glass rod or tobacco-pipe, you find the
iron dissolves more slowly: by keeping a little iron at the bottom, and
occasionally adding the acid, you may always have this preparation at
hand.
It is to be used thus:—having a copper of hot water ready, put a part of
it to some cold in a flat tub till the mixture is as hot as the hand will
bear; then, according to the paleness or fulness of your pattern, add
some of the solution of iron, and mix it well by stirring: begin with
about half a pint for two pieces of twenty-four yards each: it is best to
add a smaller quantity than is necessary first, as you can make another
addition as you please, but, if you add the solution in excess, to
diminish it is by no means so easy. Now, having ready a flat tub with
water of as hot a temperature as the hand will bear, put into it a clear
solution of pearl-ash, and have also ready another tub of clear cold
water to wash off in; then pass the pieces (always taking care to have
them well wetted out in one of the tubs of hot water before either the
solution of iron or pearl-ash is put into either of them) through the
solution of iron six or seven times, edging them over by the selvage to
keep them even; next, folding them first even upon a board, wring them
out, wash them off and pass them through the solution of pearl-ash;
lastly, wash them off again in fresh and clean water: a permanent and
bright buff will be found, and as good a colour as can be dyed upon
cotton.
We here see what an affinity iron and cotton have for each other when the
iron is combined with an acid and the combination in a liquid state.
Although the colour is not so beautiful in every instance, yet, be the
acid which dissolves the iron what it may, cotton imbibes the iron from
it.
What is left of the solutions of iron and the pearl-ash may each be kept
in a separate _deal_ tub for use.
_To dye cotton_ PINK.
Take _safflower_ in proportion to its goodness and the quantity of work
to be dyed; put it into pure and clear water; tread it in the water till
the water becomes fully charged with a kind of extractive yellow colour.
It is best to put the safflower into a strong linen bag or sack; a sack
containing sixty pounds will take a man two days to wash it clean: if
done in a clear running stream the yellow colour will of course run away;
if you have a small quantity in a tub it must be let out at a plughole,
which every flat tub should have. _The safflower must be worked or trod
till all the yellow colour is got out of it, or the_ pink _to be obtained
from it afterwards will not be bright._
When the safflower is thoroughly washed, take it out of the bag and put
it into a deal tub or trough, and add to it _pearl-ash_ in the proportion
of six pounds to one hundred pounds of the safflower, which should be
weighed before it is wetted. Let the potash be well dissolved in water;
pour part of the clear solution off, and mix it thoroughly with the
safflower; after having stood for some time strain the liquor through a
cloth or sieve into another deal trough. The whole solution of pearl-ash
should not be put in at once, but at different times. If there should be
reason to believe that the safflower will yield more colouring matter by
a farther addition of the solution of pearl-ash, such additional solution
may be made. The water for the solution and the solution to the safflower
should both be applied cold. Carbonate or mild potash is better than the
caustic. By putting the solution of pearl-ash on the safflower at
different times it will be readily seen when the fluid passes through the
cloth or sieve free from colour.
The colour is of a cherry hue, and is resinous, therefore the water
dissolves but little of it; the carbonate of potash is added to dissolve
this resin.
To overcome the influence of the pearl-ash, which tinges the red of a
yellow colour, some cream of tartar must be finely powdered and dissolved
in boiling water, and added to the liquor when it is nearly cold. In the
South of France lemon juice is used.
The colour, being thus raised by the cream of tartar, is now to be mixed
with cold water in proportion to the fulness of the pattern desired, and
the cloth must be worked six or seven times in it, as in other colours.
What is left of the colour must be taken up with some skein cotton, and
dried; this may be added to water upon another occasion by saturating the
acid with a solution of pearl-ash, which will abstract the dye from the
cotton.
The solution of tartar will again redden the colour from the yellow of
the pearl-ash; this must be done if any remain, for it will not keep in a
fluid state.
We shall not here describe any other process with cotton till we have
treated of wool and silk.
For dyeing cotton _black_, and some other colours, see the chapters V.
and VI.
[7] The difference between _decoction_ and _infusion_ should be always
carefully observed: a _decoction_ is made by _boiling_ the ingredient or
ingredients in any liquor; an _infusion_ is that in which the ingredients
are put but _not boiled_.