THE BASIC COLORS
In an earlier chapter it was mentioned that the modern dyestuffs
originated with the discovery by Perkin, in 1856, of the violet
coloring matter known as Mauveine. This dye was made by the oxidation
of the then rare chemical, aniline. Following this discovery, other
chemists, especially in France and Germany, soon obtained from the
same chemical or from substances very closely resembling it, a
considerable quantity of powerful and brilliant dyestuffs of the same
general character.
The original Mauveine was before long superseded, first by Hofmann’s
Violet, and then by a very important series of violet and purple
dyes known as Methyl Violet, with shades ranging from 6 or 7B for
the deep, full purples, to the 6 or 7R for the very red shades.
These violet colors have never been surpassed, or even equalled by
any other dyes for brilliancy and richness, although, in common
with almost all the other dyes of this class, they are not fast to
sunlight.
Another extremely powerful and brilliant color of this class, used
considerably to this day although discovered nearly fifty years
ago, is the dye often called, from its origin, Aniline Red. It was,
however, named by the German manufacturers, Fuchsine, from its
rich, full, crimson shades, resembling the deep tints of the flower,
fuchsia, while the French, who discovered and manufactured it soon
after the close of Louis Napoleon’s Italian campaign, called it
Magenta, after the famous victory of that name.
About this time some German chemists discovered and introduced a
full, rich, brown dye, still largely used for dyeing leather (kid
gloves and the like), and, naturally enough, gave it the name of
Bismarck Brown. And at approximately the same date was discovered the
very valuable blue dyestuff, perhaps the best of the whole class,
with quite a range of full, deep shades, and with considerable
fastness to light, called Methylene Blue.
=General Properties.=—The early colors of this group are the
dyestuffs properly known as the “Aniline Colors” because of their
origin; although this name has been applied, loosely, to all of
the thousands of artificial dyestuffs without regard to their
source of composition. To the chemist, their chemical structure
and their behavior toward reagents, such as acids and alkalies,
naturally suggested the name “Basic Colors.” This means that they are
substances with strong affinity for all sorts of acids, with which
they form more or less stable salts, while they can be liberated from
these salts by the action of stronger bases, such as ammonia, or the
fixed alkalies, soda and potash.
=Application.=—These facts were discovered by Perkin while trying to
introduce his Mauveine into the dyeing industry, and he discovered
the methods, used to this day, for applying these dyes to the
different textile materials. He found that the dyes of this class
have a strong affinity for the different animal fibres, such as
wool, silk, leather, etc., all of which seem to possess some acid
properties of their own; but pure vegetable materials, like cotton,
linen, and paper, from which all impurities such as vegetable acids,
gums, etc., have been removed, have no affinity at all for even the
most powerful of the Basic dyes. A cotton handkerchief, boiled for
hours in a strong solution of Methyl Violet, can be washed in a few
minutes clear of every particle of color, while a piece of silk or
wool, soaked for an instant in the same dye-bath, will be permanently
stained, deep and full.
_Cotton, Linen, etc._—In order to fasten these dyes to vegetable
fibre it is necessary to give the latter a distinctly acid character,
and this was done by Perkin in a manner still used. He steeped the
material for several hours in a hot bath of the acid vegetable
compound, tannic acid or tannin, found so largely in hemlock and
chestnut bark, sumac leaves, nut-galls, and the like; and then
loosely fixed the tannin, thus absorbed, by a weak bath of tartar
emetic. Cotton or linen fabrics, thus “mordanted,” will combine with
the Basic dyes as readily and as firmly as any animal fibre, and the
resulting colors, while not, as a rule, fast to light, are extremely
fast to washing.
Since the introduction of the direct cotton dyes, both Salt colors
and Sulphur colors, this method of dyeing, for skeins or piece goods,
has been largely discontinued; but, by using a modification of this
process, enormous quantities of Basic colors are still employed,
on cotton and linen, in the manufacture of calicoes, organdies, and
other printed fabrics.
Curiously enough the Salt and the Sulphur colors, in almost every
instance, possess sufficient acid properties of their own to act
as very fair mordants for the Basic colors. Accordingly, it is not
uncommon for dyers to “top,” with Basic colors, cotton or linen goods
dyed directly. In the case of the Salt colors, this increases their
fastness to washing, and with Sulphur colors it makes the shades more
brilliant.
Most vegetable materials that are used in a more or less natural
condition, like straw, raffia, grass, wood-shavings, jute, and the
like, contain enough of this natural tannic acid to act as a mordant
for the Basic colors, which may in this direction be used as direct
dyes.
_Wool, Silk, etc._—For animal fibres, such as wool, silk, furs,
feathers, etc., the Basic colors have been almost entirely
superseded, in commerce, by the class of dyestuffs known as the Acid
colors. These occur in much greater abundance and variety, and can
be applied with less danger of spoiling the goods by uneven results.
For leather, on the other hand, the Basic colors are still largely
used, especially for dark shades, or when fastness to light is not
particularly desired. On bark-tanned leather, which is full of tannic
acid, they take hold particularly well, and are often more convenient
to work with than the Acid colors, although they do not, as a rule,
give such even results.
=Uses.=—On a small scale it is hardly worth while for the amateur to
try to use these Basic colors for dyeing either cotton or linen. The
difficulty of correctly and evenly mordanting the goods is quite as
great as that of applying the dyes afterward. And the Sulphur colors
and Vat colors will be found quite as fast to washing as the best
mordanted Basic colors, with the additional advantage of being very
much faster to light, as well as easier of application.
By using some of the methods of the calico printer, it is possible to
employ these dyes, with some success, for stencilling. But even for
this purpose, excepting, perhaps, on silk, the modern Vat colors are
more convenient, as well as being infinitely more permanent to light.
_Disadvantages._—The chief drawback to the use of these dyes is
that they are not fast to light. Several of them—Methylene Blue,
for instance, and Methylene Heliotrope O (_Metz_)—are fairly fast,
but the rest, especially in light shades, and on transparent or
translucent fabrics, are liable, when exposed to sunlight for any
length of time, to alter their shade to a very marked degree.
For dark shades this is not so noticeable, for, when goods are
strongly colored, the effect of the sunlight on at least the deeper
portions of the fibre is largely counteracted by the color of
the goods themselves. So, too, an opaque material, like leather,
will hold the same shade of color distinctly longer than silk or,
especially, artificial silk, where the sunlight strikes through and
through the fibre, without any protection at all. But, generally
speaking, these dyes will not stand strong sunlight.
Nor are the shades of these Basic dyes, as a rule, as attractive as
those of other classes. The strong and brilliant, not to say coarse,
shades of Methyl Violet, Malachite Green, Aniline Red, and the rest,
which created such a sensation when they first appeared in the early
sixties, were the particular colors which provoked John Ruskin to
vehement, if not unparliamentary remarks. When unmixed they certainly
do harrow the feelings of those artistically inclined, as much now as
then. They are rarely seen now, for the taste of the public has been
sufficiently educated to make a demand for softer shades. As before
explained, nothing is easier than to soften these fierce, harsh
colors to most beautiful and harmonious tints by mixing into them a
mere trace of their complementaries.
_Advantages._—In spite of all that can be said against them, these
cheap, brilliant, and very powerful dyes are not to be despised, and
should still be found in the outfit of a well-equipped dyer. For
straw, raffia, chips, willow, and other materials used so largely
for hats and for basket-work, these dyes are distinctly valuable,
and, if supplemented by fast Acid colors for light shades, or for
particularly fast effects, will be found satisfactory enough. So,
too, for leather they will be found extremely useful, excepting where
delicate shades, fast to light, are required.
Some kinds of artificial silk, also, especially those made from
nitro-cellulose and hence possessed of acid properties, dye far
better with these than with any other dyes, although, as explained
above, the colors will be far from permanent.
For the craftsman, the fastness to washing of these dyes is a
matter of very little importance, because they are used by him so
exclusively upon materials such as basketry, leather, and artificial
silk, which are never exposed to rough handling in boiling soap and
water.
As regards their fastness to light, the greater number of these
must be classed as belonging to the fourth class, i.e., distinctly
fugitive in character. On the other hand, some special ones can be
selected from the group which are not only distinctly faster than the
rest, but are fast enough to be well up in the third class, or can at
a stretch, be placed in the second class, i.e., can be considered as
satisfactory, at any rate, against any but very severe exposure.
=The Fastest Basic Colors.=—Among these may be placed the well-known
dyestuff, Methylene Blue, perhaps the most satisfactory of the whole
class. A very good color also is Methylene Heliotrope O (_Metz_),
which, while less brilliant, is far faster than the many brands of
Methyl Violet, Hofmann’s Violet, and the rest, which to most dyers
are the characteristic basic violets.
For blacks, many composite dyes are on the market, made by the
different color houses, known as Leather Blacks. These are fast
enough, for deep shades, but not to be trusted when thinned down to
form greys. The fastest individual basic black is Diazine Black,
(_Kalle_), and this should be used for the lighter shades.
The Red and Yellow colors are distinctly less satisfactory. None of
them can really be considered better much than third class. Of the
Reds the best is probably the color known as Safranine, different
brands of which, giving as a rule the yellow shades, are manufactured
by the various color houses; one brand being about as fast as
another. For the bluish shades of red, probably the fastest is
Diazine Red, (_Kalle_).
As regards Yellow, the list is even more unsatisfactory.
There is a very beautiful golden yellow, known as Auramine O,
manufactured by most of the color houses, which, however, is hardly
fast enough to be in the third class. This dyestuff, by the way, is
injured by boiling, and therefore should never be used in a dye-bath
heated to over 130° or 140° Fahrenheit. Less pleasing in shade,
but somewhat faster to sunlight, are the rather orange or brownish
yellows known as New Phosphine G (_Cassella_), and Methylene Yellow
(_Metz_). Somewhat brighter colors, though less fast to light, are
produced by Thio flavine T. None of these, however, compares in
fastness to the selected colors of any other class in this book.
The various brands of the common dyestuff, Bismarck Brown, are
largely used for leather, and while probably inferior in fastness
to any of the colors mentioned above, are not found in commercial
practice too fugitive to be pretty satisfactory. When, however,
materials are liable to be exposed for any length of time, two or
three weeks in succession, to direct powerful sunlight, it will
generally be advisable to use mixed browns made from fast Acid colors.
Upon the whole, although we are still frequently called upon to
employ them, they must, from the craftsman’s standpoint, always be
considered as untrustworthy. They should, therefore, never be used
where dyestuffs of any other class can be made to take their place.
DYEING DIRECTIONS
The application of Basic colors to leather dyeing will be discussed
later. We shall now discuss their application to basketry materials,
such as straw, raffia, willow, and the like, where they will be found
useful.
It will at once be noticed that these dyestuffs are far more powerful
than any thus far met with in these lessons. Indeed, while there
will be needed, for full shades of the Vat colors, pastes from about
15% to 20% of the total weight of the dry materials, of the Sulphur
colors from 7% to 10%, of the Salt colors from 4% to 6%, and of the
Acid colors from 1½% to about 3%, most of these Basic colors will
give very full shades with from ½% to 1% of the total weight of dry
material.
These Basic colors do not dissolve readily in water, but are easily
soluble in alcohol, and also in even very dilute acids. Acids form
salts with the dyestuffs and these salts dissolve when the free
coloring matters do not. Accordingly the Basic colors should always
be dissolved carefully in a separate cup or vessel, using hot water,
and adding, for each spoonful of dyestuff, two or three spoonfuls of
acetic acid or, if more convenient, of strong vinegar.
The color, thus dissolved, should be added to warm water in the
dye-pot, preferably through a fine strainer or piece of cheesecloth,
to avoid any undissolved particles which would cause spots. The
well-wetted goods are immersed in this dye-bath, and turned, either
in the cold or with gentle heat, until the desired shade is reached,
or the bath is exhausted. The material is then taken out, rinsed once
or twice in water, cold or warm, carefully dried, and, if necessary,
straightened and pressed or ironed out.
_Straw._—Care must be taken when dyeing these materials to have them
quite free from grease and dirt, before dyeing them. If they do
not wet readily and evenly, after being soaked in warm water for a
couple of hours, they should be carefully washed in warm soapsuds,
and thoroughly rinsed. The soap, however, should be of good quality
and, especially with straw, either in the form of straw braid or made
up into hats, no soda or other free alkali should be allowed in the
bath, for fear of injuring the surface and destroying the gloss. This
last is sometimes improved by dipping the straw, after dyeing and
rinsing, into a weak bath of Castile (olive oil) soap, or of Turkey
red oil (about one tablespoonful to the gallon), before it is dried.
In dyeing straw, the greatest pains must be taken to dye it evenly.
Braid should be tied up in loose hanks or bundles, so that the
dyestuff can penetrate readily into every part; and with a loop
of tape or string, by which it can be raised or lowered in the
dye-bath. It should be kept in motion sufficiently to cause uniform
circulation of the liquid. The dye-bath should not be too strong,
especially at the beginning, and should be heated slowly to the
boiling point, where it should be kept for half an hour or so, to
insure penetration. It is best to add the dyestuff in small portions,
from time to time, as the bath becomes exhausted, lifting the goods
out of the bath each time, and stirring in the new color before
putting the goods back again. If the goods once become uneven it is
very hard, if not impossible, to get them level again, or to strip
them fully, without spoiling the materials. The best thing to do, if
this misfortune overtakes them, is to dye them some dark color, where
minor irregularities will be covered up and pass unnoticed. In other
words, “Dump it in the black,” as the dyers say.
Ladies’ straw hats are dyed in just the same way as the loose braid,
the same care being taken to clean and wet the goods thoroughly, and
to dye evenly. It is often of interest to experiment with old hats
of good material, but faded, and to dye them up some pleasant new
shade, and the ribbons and trimmings to match. Sometimes the remains
of the old coloring will strip well by washing in hot soapsuds, and
sometimes by soaking in warm water containing about one tablespoonful
to the gallon of _sodium hydrosulphite_—the same salt that was used
as a reducing agent for the Vat colors in the last chapter.
If the color comes out well, it is then easy enough, after thoroughly
rinsing, to dye them any desired shade. Otherwise they can be dyed
Navy Blue, with a good shade of Methylene Blue and a trace of red,
or Seal Brown, using a large amount of red and a little yellow and
blue; or they can be dyed black with a black dye, such as one of the
so-called Leather Blacks, usually made by mixing a deep purple with a
yellow, or one of the strong, powerful Basic greens with red.
In general, a well dyed piece of braid is supposed to show smooth,
even coloring, good gloss, and good penetration of the dyestuff into
the folds of the straw. There are, however, decided possibilities
for the intelligent worker to obtain more interesting effects with
but little trouble. It is very easy to use the principles, already
explained, of rainbow dyeing, for straw braid, and beautiful effects
can be obtained in this way, though it would need an artistic as well
as an experienced milliner to fully utilize the same in making hats.
But it frequently happens, when dyeing coarse braid without boiling,
that the dye penetrates unevenly, from the edge towards the centre.
Very pretty shaded effects can be produced in this way, the general
color being uniform, and yet the straw, when looked at closely,
showing tints instead of one flat, uniform shade. By dyeing the straw
a solid color first, and then shading it in this manner with a
different color, very interesting effects can be produced.
It may be worth while to mention here that, when bought at wholesale
places, it is astonishing how cheap the raw materials are. Bodies
of straw, chip, etc., framing wire, white satin ribbon, artificial
flowers, wing feathers, etc., from which not only pretty but even
handsome and elegant head coverings can be created, and cost next to
nothing at wholesale. The mechanical part of dyeing all these things
can be learned in a very short time; after that the possibilities for
a skilled worker, who has a good eye for color and can dye to the
desired shades herself without having to hunt them far and near, are
very large.
_Raffia._—This is a material so widely used in the public schools,
as well as by craftsmen, for weaving baskets, that it is well worth
while to pay more attention to the dyeing of it. It is quite cheap,
and very bulky, and takes these colors extremely well. So that it is
one of the most satisfactory of all raw materials to experiment with,
especially if there is a school or workshop at hand, where the dyed
goods can be utilized.
The raffia should be shaken out thoroughly, and soaked in soft water
over night, or at least for several hours, to thoroughly wet and
soften it. If even shades are desired it can then be dyed, just like
straw braid, in a warm dye-bath containing the dyestuff, previously
dissolved in diluted acetic acid or vinegar.
It is much more interesting, however, to dye it rainbow shades
from the start. If red, blue, and yellow dyestuffs are dissolved
separately, in different cups or pitchers, these solutions can be
used to replenish the large dye-pots of the same colors. To keep the
colors reasonably clear, and prevent them from speedily degenerating
into “mud,” it is well to keep on hand one or two rinsing-pots,
full of warm water, or to have a sink near at hand, where each hank
or bundle of raffia should be rinsed after being taken out of one
dye-pot and before going into the next.
The raffia, when thoroughly wetted out, should, for convenience’
sake, be made up into separate loosely-tied bundles, with a loop
on each by which to handle it in the dye-bath without staining the
hands. It is well, too, to have some oil-cloth around, for these
bundles drip a good deal, and the dye-liquor will stain anything of
an animal or vegetable nature with which it comes in contact. After
a little experimenting with dipping these bundles first into the
first dye-pot and then—rinsing each time—into the other two, it will
be easy to get the general effect of any particular shade, although,
when examined closely, the fibre will show the presence of all three
colors.
It is interesting to notice, here, as previously with the Salt
colors, how easy it is to modify and soften the harsh shades of the
individual unmixed dyestuffs. And, as before, it is very interesting
as well as very useful to dye some bundles even shades of some
important compound color, such as brown, for instance, or olive
green, or steel grey, and to notice how the color is changed on the
fibre by adding a little more red, or yellow, or blue to the bath.
The “eye for color” obtained in this way is of the greatest possible
advantage to a dyer, whether amateur or professional; and where, as
in this case, the materials are cheap, easy to dye, and possible to
utilize, every advantage should be taken of the opportunity.
=Permanent Colors on Basketry.=—While for most purposes the straw,
raffia chips, willows, etc., dyed with Basic colors will be found
satisfactory enough, it is best for craftsmen who are making a
specialty of very high-grade baskets, to use some of the fast Acid
colors, described and listed in the next chapter, for their reds and
yellows, and for all mixed shades in which these two colors play an
important part. The Acid dyes are applied in a boiling bath, with the
addition of a little acetic acid, and, while not fast to washing,
and not imparting their colors as readily as the Basic dyes, can be
thoroughly depended upon, even in light and delicate shades, against
the action of sunlight. Salt dyes can also be used, in a boiling
bath with the addition of some salt, but, excepting in some special
cases, are not superior to the Acid dyes, although somewhat faster to
washing.