For example, the lines of an engraved copper-plate are
filled with powdered albumen. On the other hand, a few drops of
hydrofluoric acid are spread over a wooden board, and the powdered
engraving is exposed for ten to fifteen seconds to the fumes
disengaged by holding it about a quarter-of-an-inch above the board.
The acid is absorbed by the powdered albumen without attacking the
copper. If this plate be now placed in close contact with any surface
(metal, paper, or glass) which has been covered with a coating of
sugar and borax, and dried immediately, a deliquescent fluoborate of
soda is produced under the action of the acid vapors, the sugar
becomes tacky, and, by brushing a powder over this surface, the image
appears immediately.
In M. Davanne's opinion this new invention of M. Garnier's seems
likely to have a useful and extended application. The image may be
made with powder of any desired color. If it is on glass, it may be
transferred to paper or other support by means of collodion or
gelatine. By employing enamel powders, this process gives a new method
of producing vitrified images. It may also be used as a simple method
of reproducing engravings under certain circumstances; copies of
diagrams, however intricate, could easily be produced on glass by it,
and used for the illustration of lectures by means of the magic
lantern.
Pages:
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159