US296391A - Art of printing by sunlight or other light - Google Patents

Description

E. COPE.

: (K0 Model.)

ART OFPRINTING BY SUNLIGHT OR OTHER LIGHT, AND APPARATUS THEREFOR. No. 296.391. Patented Apr. 8, 1884.

Witnesses Inventor springs or clamps.

Umrnn STATES PATENT @FFICE.

EZRA corn, or HAMILTON, oruo.

ART OF PRINTING BY SUNLIGHT OR OTHER LIGHT, AND APPARATUS THEREFOR.

SPECIFICATION forming part of Letters Patent No. 296,391, dated April 8, 1884.

Application filed January 5, 1884.

.To all whom it may concern/.

Be it known that I, EZRA COPE, of Hamilton, Butler county, Ohio, have invented certain new and useful Improvements in the Art of Printing by Sunlight or other Light, and

Apparatus therefor, of which the following is a specification.

. This invention pertains to a method of and an apparatus for securing together the transparent negative and the sensitive paper or other tissue in the operation of sun-printing. The photographer lays his sensitive paper against a yielding pad and forces his glass negative tightly down upon it by means of The latter-day draftsman uses a drawing made upon paper more or less transparent for a negative. He lays his sensitive paper upon the pad, the same as the photographer. Helayshislimp negativeupon the sensitive paper. He lays a plate of glass over the negative and clamps the Whole together, the same as done by the photographer. He requires the glass for the purpose of transmitting pressure from his clamps to all parts of the negative. The modern blue-print process has brought into'practice the art of sunprinting upon sheets of very much greater size than formerly dealt with in connection with glass negatives. This has required that the glass plate used by the draftsman be of i great thickness and strength, and with very skillful manipulation and judicious choice of glass and padding it has been found almost impossible to secure perfect contact between the limp negative and the transparent paper at all parts of their surfaces. A failure on the part of the negative to make perfect contact with the sensitive paper at all points is fatal to the perfection of the sun-print. Even with the thickest glass the clamping pressure must be applied entirely at the edge of the glass, and it seems almost impossible to secure glass of sufficient stiffness and strength to prevent breakage if pressed sufficiently, or lack of contact if pressed insufficiently. In my invention I apply pressure uniformly over the entire surfaces of the negativea result which I produce by exhausting the air from between the negative and the sensitive paper, thus permitting the atmosphere to exert its pressure to press the negative and sensitive paper into perfect contact.

(No model.)

and adapted to have the air exhausted from its interior, in order that the atmosphere may exert a collapsing pressure upon it. This collapsing pressure is utilized in forcing the negative into perfect contact with the sensitive paper.

In the drawings, A represents, say, a drawing-board or table-top pertinent to the device under consideration only as a support; B, an air-tight envelope; 0, an exhaust-tube communicating with the interior of the envelope; D, a paper negative as produced by a draftsman; E, a drawing upon the same; F, a sheet of sensitive paper under the same; G, the top layer of the envelope, which is of transparent material; H, the bottom layer of the envelope,

and I the receiving-space of the envelope between its upper and lower layers.

The upper layer, G, of the envelope may be of stiff material, as glass, or it may be of limp material, as transparent paper or other tissue. It must possess the proper degree of transparency to allow the sunlight to go through it.

The lower layer or back, I, of the envelope may be of any suitable'material, stiff orlimp; but it is necessary that either the back or front of the envelope be sufficiently limp to collapse fairly against its fellow. The back and face of the envelope are united at the edges by lapping and sealing or other efiective manner. The sensitive paper and superposed negative being inserted in the envelope, the end of the envelope is to be held closed by a clamp or weight, if requisite; but I find in practice that the open end of the envelope tends to close itself airtight when the air is exhausted.

through the tube 0 by means of any apparatus adapted for the purpose. The result is an atmospheric pressure upon the external surfaces of the envelope, tending to press the sensitive paper and negative together with a force ap plied uniformly over the surfaces.

It is not essential that the transparent paper and the negative should be placed within the envelope, as they may, if desired, be made to form an envelope by simply having their edges properly united and being placed in a proper position with reference to each other, an exhausting-tube being fitted at some point of the edge to communicate with the space between their surfaces.

The limp negative of the draftsman may itself be attached to his sensitive paper, or the sensitive paper of the photographer may be attached directly to his glass negative. Thus, in Fig. 2, the upper layer of the envelope may be the dral'tsinan s limp negative, and thelower layer, H, his sensitive paper, secured thereto at the edges, and l the intervening space to be suppressed by the exhaustion of the air.

In Fig. l the upper layer, G, of the envelope may be the glass negative of the photographer, the lower layer, H, of the envelope his sensitive paper, secured thereto at the edges, and I the intervening space to be suppressed by the exhaustion of the air. In Fig. 3 the upper layer, G, may be the limp negative of the draftsman; H, the lowerlayer of the envelope, of any thickness desired, attached thereto at the edges; and I, the intervening space to receive the sensitive paper and be suppressed by the exhaustion of the air.

I claim as my inventionl. In a sun-printing apparatus, an envelope provided with an exhaust-aperture, and having one of its layers of proper transparency, and one or both of its layers of collapsible limpness, substantially as and for the purpose specified.

2. In asun-printing apparatus, an envelope provided with an exhaust-aperture, and having one of its layers of proper transparency, and one or bothof its layers of collapsible limpness, and adapted to receive a sensitive sheet or a negative, or both, substantially as and for the purpose specified.

The improvement in the method of secun ing close contact between the negative and sensitive sheet in the art of sun-printing, which consists in connecting them together and exhausting the air from between them, substantially as set forth.

EZRA COPE.

Witnesses:

J. .V. SEE, \V. A. SEWAJH).

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