PHOTOGRAPHIC PRINTING BY VAPOR--ATMOGRAPHY.

This process consists in tracing or transferring by means of vapors or

fumes an image of any object from one surface to another, whence the

name of atmography it is proposed to give it. The operations are as

follows:

When an image formed of a powdery substance has been obtained either

by dusting (as described above), or by filling an engraved plate with

the powder, the plate bearing the image is exposed to a vapor, which

has no effect upon it. The powder alone absorbs the vapor, and if the

plate be then applied to a surface coated with some substance capable

of being acted upon by the vapor, an image is obtained upon this

second surface. 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.--_Photo. News._

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Scientific American Supplement, No. 312, December 24, 1881 · 第 73 / 76 题