In olden days, a tanner gained his reputation
for a certain type of leather based largely on the peculiarities
of a certain type of hide or skin and from the tannin obtained
from the local trees. However, in the wake of steamship and
railway, it became possible for the tanner to obtain his raw
materials from anywhere in the world. At the same time, new
chemicals and processes were being discovered in the laboratory.
After hides and skins are removed from the animals, most
are subjected to a preliminary curing treatment so that they
do not putrefy before reaching the tanner. This treatment
varies according to climate and the availability of salt.
In hot dry climates, they are either dried out thoroughly,
or salted and dried, while in cold damp climates, they are
well salted and stacked in the wet condition. Each curing
method presents challenges to the tanner, and the skins must
be soaked in water until they reach a state approximating
the fresh skin. |
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Skin is composed of three layers, and the tanner is interested
in the central one. The outer layer of hair is removed by soaking
in lime. Often accelerating agents are added to hasten this
process. Despite this chemical treatment, the hairs are merely
loosened and must be pulled out. Then, the leather can be washed
and dried for the next step. |
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Fleshing involves scraping any remaining flesh and fat from
the inside of the skin. While this process is now done mechanically,
it was once performed by hand. It was incredibly unpleasant
work. |
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Next comes the bating process. This was essential, despite
the unpleasant methods historically employed, to bring out the
grain of the leather. The tanner soaked the skins in fermented
bran to reduce the alkalinity, then paddled them in warm water
containing hen and dog dung until the skin became soft, smooth,
with a silky grain. Now, other chemicals are used to achieve
this end. |
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Scudding follows. The skins are placed over a curved block
and scraped by hand with a two-handled curved knife. This cleans
and opens out the pores. This can be done by machine, but results
are not nearly as regarded as hand-scudding. |
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At this point, the hide is ready for tanning. Vegetable tanning
is a very old process that involves the use of tree bark, leaves,
or seed pods. The quality of the leather is as much determined
at this stage as in any other. Some tannins create a soft, pliable
leather; others a firm, rigid leather. Tannin selection depends
on the intended purpose of the finished leather as well as the
type of skin and how it has been prepared. Tannins also impart
color to the skin. |
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After tanning, the leather may undergo a number of other processes:
dying, scraping, chemical treatment, etc. depending on the desired
finished product. |
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