DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20658#0387
APPENDIX.
373
LITHOGRAPHY.
LITHOGRAPHY is a new method of printing, differing in its fundamental principles from
all other methods now in use; and may be distinguished by the name of Chemical Printing.
In this process it does not matter whether the lines be engraved or elevated ; but the lines and
points to be printed are to be covered with a liquid, to which the ink, consisting of an homo-
geneous substance must adhere, according to its chemical affinity and the laws of attraction.
At the same time, all those places that are to remain blank, must possess the quality of repelling
the colour. These two conditions, of a purely chemical nature, are perfectly attained by the
chemical process of printing. For common experience shews that all greasy substances, such
as oil, butter, &c. or such as are easily soluble in oil—as wax, bitumen, &c. do not unite with
any watery liquid without the intervention of a connecting medium; but that on the contrary,
they are inimical to water and seem to repel it. The principal dissolving and uniting liquid
for the above-mentioned substances is alcali, which by proper management, forms a sort of soap,
soluble in water. Upon this experience rests the whole foundation of this new method of
printing. Amongst the different materials applicable to this new method of printing, the calca-
reous slate occupies the first place. It possesses not only a strong tendency to combine with
unctuous substances, and to retain them obstinately; but it likewise possesses the power of ab-
sorbing bodies of a different nature, such as aqueous fluids. In this state it repels unctuous
bodies. This excellent quality, with the ease with which they are prepared, renders them supe-
rior to all other substances.
A perfect stone ought to be of the following description : viz.—It should be from one inch
and a half to two inches and a half in thickness, free from stains and white spots, and rather
hard; a soft stone being of little use, as the lines spread and soil.
TO PREPARE STONES FOR DRAWING OR WRITING.
Particular care must be taken that the stone be perfectly level: if otherwise, the drawing or
writing will not print where the stone is hollow. A large piece of pumice stone is most desirable
with fair water, for rubbing the stones down. If to be prepared for transfer drawing or writing,
to get it level is all that is required. Wash it free of the pumice with clear water, and let it dry.
When used rub it slightly with a dry piece of pumice that has a fair surface; taking care to free
the stone from dust before the drawing is transferred.
For writing or drawing on the stone with the pen, the higher polish the stone has the better:
after being finished with pumice stone and water, polish it with snake stone.
A stone for chalk drawing must have a rough-grained surface: to effect which, take two
level stones; sift some fine sand on the surface of one of them, with a little fair water; then the
two must be rubbed together in all directions. At intervals more sand must be sifted, and more
water applied. The longer the rubbing is continued, without adding more sand, the finer the
grain will become. The oftener sand is applied, the opener and coarser the grain. In this
o c manner
373
LITHOGRAPHY.
LITHOGRAPHY is a new method of printing, differing in its fundamental principles from
all other methods now in use; and may be distinguished by the name of Chemical Printing.
In this process it does not matter whether the lines be engraved or elevated ; but the lines and
points to be printed are to be covered with a liquid, to which the ink, consisting of an homo-
geneous substance must adhere, according to its chemical affinity and the laws of attraction.
At the same time, all those places that are to remain blank, must possess the quality of repelling
the colour. These two conditions, of a purely chemical nature, are perfectly attained by the
chemical process of printing. For common experience shews that all greasy substances, such
as oil, butter, &c. or such as are easily soluble in oil—as wax, bitumen, &c. do not unite with
any watery liquid without the intervention of a connecting medium; but that on the contrary,
they are inimical to water and seem to repel it. The principal dissolving and uniting liquid
for the above-mentioned substances is alcali, which by proper management, forms a sort of soap,
soluble in water. Upon this experience rests the whole foundation of this new method of
printing. Amongst the different materials applicable to this new method of printing, the calca-
reous slate occupies the first place. It possesses not only a strong tendency to combine with
unctuous substances, and to retain them obstinately; but it likewise possesses the power of ab-
sorbing bodies of a different nature, such as aqueous fluids. In this state it repels unctuous
bodies. This excellent quality, with the ease with which they are prepared, renders them supe-
rior to all other substances.
A perfect stone ought to be of the following description : viz.—It should be from one inch
and a half to two inches and a half in thickness, free from stains and white spots, and rather
hard; a soft stone being of little use, as the lines spread and soil.
TO PREPARE STONES FOR DRAWING OR WRITING.
Particular care must be taken that the stone be perfectly level: if otherwise, the drawing or
writing will not print where the stone is hollow. A large piece of pumice stone is most desirable
with fair water, for rubbing the stones down. If to be prepared for transfer drawing or writing,
to get it level is all that is required. Wash it free of the pumice with clear water, and let it dry.
When used rub it slightly with a dry piece of pumice that has a fair surface; taking care to free
the stone from dust before the drawing is transferred.
For writing or drawing on the stone with the pen, the higher polish the stone has the better:
after being finished with pumice stone and water, polish it with snake stone.
A stone for chalk drawing must have a rough-grained surface: to effect which, take two
level stones; sift some fine sand on the surface of one of them, with a little fair water; then the
two must be rubbed together in all directions. At intervals more sand must be sifted, and more
water applied. The longer the rubbing is continued, without adding more sand, the finer the
grain will become. The oftener sand is applied, the opener and coarser the grain. In this
o c manner