89. Coloured impressions of leaves upon paper may be made by
a kind of surface printing. Such leaves are chosen as have
considerable inequalities: the elevated parts of these are
covered, by means of an inking ball, with a mixture of some
pigment ground up in linseed oil; the leaf is then placed between
two sheets of paper, and being gently pressed, the impression
from the elevated parts on each side appear on the corresponding
sheets of paper.
90. The beautiful red cotton handkerchiefs dyed at Glasgow
have their pattern given to them by a process similar to
stencilling, except that instead of printing from a pattern, the
reverse operation that of discharging a part of the colour from a
cloth already dyed--is performed. A number of handkerchiefs are
pressed with very great force between two plates of metal, which
are similarly perforated with round or lozenge-shaped holes,
according to the intended pattern. The upper plate of metal is
surrounded by a rim, and a fluid which has the property of
discharging the red dye is poured upon that plate. This liquid
passes through the holes in the metal, and also through the
calico; but, owing to the great pressure opposite all the parts
of the plates not cut away, it does not spread itself beyond the
pattern.
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