Excerpt from the DYING OF WOOLEN FABRICS
Indigo is the
blue matter extracted from a plant Indigofera tinctoria and other species, growing in Asia,
South America, and
There are two
ways of dying with indigo. It may be dissolved in acid or oil, thereby making
an indigo extract. This process was discovered in 1740. It gives good blue colors, but is not very
permanent. It also does not dye cotton or linen. The other method is by the indigo vat process. This produces fast colors, but it is
complicated and difficult.
In order to
color with indigo, it has to be deprived of its oxygen. The deoxidized indigo
is yellow and in this state soaks into the woolen fiber. The more oxygen is removed from the indigo,
the brighter and faster will be the color.
For wool dying, the vats are heated to a temperature of 50º C. Cotton and linen are generally dyed cold.
1 lb. oil of vitriol (pure, not commercial).
2 oz. finely ground Indigo.
1/2 oz. precipitated chalk.
Mix a little of
the indigo with a small quantity of oil of vitriol, add a little chalk and stir
well. Go on mixing gradually till all is used up. This should take an hour or
two. Stir a few times each day for 4 or 5 days, adding about 1/2 oz. more
of chalk by degrees. It is best mixed in a glass bottle or jar, and stirred
with a glass rod. It must be kept from the air.
Reading
Comprehension Questions
1) What was the author’s purpose in writing this
passage?
a.
to give a detailed history of indigo as a cash crop
b.
to explain how to make a dye using the indigo plant
c.
to predict the future of the indigo market
d.
to promote indigo as a fashionable color in fabrics
2) In the above passage, which of the following takes place
when oxygen is removed from the indigo?
a.
the color becomes brighter
b.
the indigo extract is produced
c.
the dye becomes weaker
d.
the process slows down
3) At the start of the 3rd paragraph of above
passage, what is the meaning of the word “deprived”?
a.
mixed
b.
combined
c.
introduced
d.
removed
4) The above passage was written for which of the following audiences?
a.
restaurant owners
b.
textile workers
c.
clothing retailers
d.
cotton farmers
5) At the end of the above passage, there is a method for
making an indigo dye. This section of
the passage can best be described as which of the following?
a.
a journal entry
b.
a recipe
c.
a diagram
d.
a census
6) The end of the above passage gives details for making indigo
extract. The mixture contains the most
of which of the following?
a.
oil
b.
indigo
c.
chalk
d.
wool
Answer Key
1)
What was the
author’s purpose in writing this passage?
a.
to give a detailed history of indigo as a cash
crop
b.
to explain how to
make a dye using the indigo plant
c.
to predict the future of the indigo market
d.
to promote indigo as a fashionable color in
fabrics
2)
In the above
passage, which of the following takes place when oxygen is removed from the
indigo?
a.
the color becomes
brighter
b.
the indigo extract is produced
c.
the dye becomes weaker
d.
the process slows down
3)
At the start
of the 3rd paragraph of above passage, what is the meaning of the
word “deprived”?
a.
mixed
b.
combined
c.
introduced
d.
removed
4)
The above
passage was written for which of the following audiences?
a.
restaurant owners
b.
textile workers
c.
clothing retailers
d.
cotton farmers
5)
At the end of
the above passage, there is a method for making an indigo dye. This section of the passage can best be
described as which of the following?
a.
a journal entry
b.
a recipe
c.
a diagram
d.
a census
6)
The end of
the above passage gives details for making indigo extract. The mixture contains the most of which
of the following?
a.
oil
b.
indigo
c.
chalk
d.
wool