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Scientific American Supplement, No. 362, December 9, 1882 by Various
page 59 of 140 (42%)
that the yellowish tinge is by no means inseparable from good results.

The washed and dried plate should appear like a design of ground and
polished glass. The ground glass appearance is given by the grain. If
there are pure high-lights (almost transparent) and opalescent shadows,
the plate is a good one.

_Printing from the Block_.--We have now a printing-block ready for the
press. If it is to be printed by machinery--that is to say, upon a
Schnell press--the surface is etched; if it has to be more carefully
handled in a hand press, etching is rarely resorted to; it is moistened
only with glycerine and water. To etch a plate for a Schnell press, it
is placed upon a leveling stand, and the following solution is poured
upon it:

Glycerine............................. 150 parts.
Ammonia................................ 50 "
Nitrate of potash (saltpeter).......... 5 "
Water.................................. 25 "

Another equally good formula, recommended by Allgeyer, who managed Herr
Albert's Lichtdruck printing for some years, is:

Glycerine............................. 500 parts.
Water................................. 500 "
Chloride of sodium (common salt)...... 15 "

In lieu of common salt, 15 parts of hyposulphite of soda, or other
hygroscopic salt, such as chloride of calcium, may be employed.

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