US1700262A - Method of making negatives - Google Patents

Description

Patented Jan. 29, 1929.

UNITED STATES PATENT OFFICE.

WILIIIAM HEINECKE, OF CHICAGO, ILLINOIS.

METHOD OF MAKING NEGATIVES.

No Drawing.

faces or photo-engravers plates and the like,

as used in photo-mechanical printing processes, in which the printing surface has to be made sensitive to light in order to receive and hold the image conveyed upon same from the negative, photographically.

According to my new method, an impression is pulled or taken on a sheet of sensitized photographic paper, film, stripfilm, glass plate or the like, from engravings or transfers on lithographic stone, or steel, copper or zinc plate or the like, or from type composition, electrotype plates and the like,

or from inked transfers on rubber blankets v or transfer paper or similar transfer mediums, or from the fingers of a person for fingerprinting purposes, by means of. printing ink or some other substance suitable for the purpose of protecting those portions of the sensitized film, paper, etc., covered with the ink against the chemical action of the reducing or developing agent, contained in the developing solution, on the silver-halids or other sensitizing agents used in the sensitized material. As the purpose of the inked impression is not to protect the portions covered with the ink or other suitable substance,

against the action of the light, but only against the contact with the chemicals contained in the developing solution and against the chemical action of same, it is not essential whether the ink, or other substance used for making the impression, is pigmented or not. It is, however, essential that the ink possesses properties which will aid in resisting sapomfication, or dissolution by the developing agents used. After developing, the negative is transferred to a fixing, bath and after rinsing to a bath in a solvent which will remove the ink, as, for example, a saturated solution of potassium bicarbonate, whereupon the negative is placed back into the fixing solution, after which it is washed, dried and ready for use. The above description of the manipulation refers more par- Application filed May 6, 1927. Serial No. 189,458.

ticularly to the use of photographicmaterial sensitized with silver-halide by way of illustrating the method. The composition of the developing agents, fixing agents and solvents used for removing the ink will vary accordingto the chemical composition and properties of the sensitizing agents and ink.

The whole operation can be performed in daylight which constitutes an important factor in the practical application of the process and its operation in printing plants for the reason that it requires no dark room or safelight, and obviates the otherwise almost insurmountable difficulties of removing to or installing machinery for pulling impressions in a dark room, or operating presses in safelight. The further object of this process is to preserve a faithful negative of printed or transferred impressions for indefinite further use.

In order to make a negative by this new direct method, I proceed as follows:

At first, I make an impression from engravings on copper plate, steel plate and the like, or from engravings or transfers on lithographic stone or zinc plate and the like, or from electrotype plates, linotype or other composition, or from transfers on rubber blankets, transfer-paper or similar transfer mediums, on a .sensitized sheet of photo graphic paper or film, or stripfilm, or glass plate, tho, if desired, the impression can also be made by drawing. This impression can be made by means of printing ink or some other substance, pigmented or unpigmented, the only requirements being that this printing element is viscous and resists the action of weak alkali solution. Thereupon, the sheet of paper or film, stripfilm or dryplate isplaced into a developing solution and devel-- oped until the entire surfaceacquires the desired density.

For the developer, I preferably use the following formula:

, Oz. Water -l 32 Sodium sulphite, 'dry 3 I-Iydrochinon 1 Formalin 1 or modifications of same, according to the results desired. After the developing, I thoroughly rinse the negative in water, whereupon I place same in a plain sodium thiosulphate bath, modifying same, when necessary, according to the requirements of the photographic material used. From the fixing bath,

venting soiling trays and hands of the operator and covering the fixing bath with an oily film or otherwise affecting same unfavorably. From the solvent, the negative is retrans ferrcd to the fixing bath, washed and dried,

, and is then ready for use.

The word film in the claims is used in a generic way to comprise all kinds of sensi- 'tized material, including paper and glass plates. The word ink in the claims is used in a generic Way to comprise all kinds of substances suitable for making an impression or transfer for the purpose of protecting those portions of the sensitized surface, covered with the impression or transfer and forming the image, against the chemical action of the developing solution and its alkaline, or acid components. Also the Word develop in the claims is used in a generic way to comprise all kinds of reducing agents reacting with the various possible sensitizing agents, as, for instance, silver-halids or ferric compounds, which are used to produce photographically a visible image. Likewise, the word sensitize in the claims is used in a generic way to comprise all kinds of emulsions, solutions and compounds used for photographic purposes and capable of undergoing such chemical changes under the action of light as an assistant factor as to produce an image, known in photography under the term of negative and by means of the contrast of the clear and opaque portions constituting the image as result of exposure to light and chemical action of the reducing agents.

I claim:

-1. The method of making a negative for use in photo-mechanical printing processes and photographic purposes, which consists in making an impression on a sensltized member, developing said member, and removing and hoto ra )hic ur oses which consists in making an impression on a sensitized member, developing said member, then fixing it, then removing the impression, and finally fixing said member.

4. The method of making negatives for use in photo-mechanical printing processes and photographic purposes, which comprises making impressions on a sensitized film, placing the same in a developing bath comprising water, sodium sulphite, hydrochinone and formalin, rinsing, removing the ink, and final- 1y fixing the film in a hypo bath, for the purpose of producing a negative.

5. The method of making negatives for use in photo-mechanical printing processes and photographic purposes, which comprises making impressions on a sensitized film, placing the same in a developing bath comprising water, sodiumsulphite, hydrochinone and formalin, rinsing, removing the ink by means of a solvent, and finally fixing the film in a hypo bath, for the purpose of producing a negative.

6. The method of making negatives for use in photo-mechanical printing processes and photographic purposes which comprises making impressions on a sensitized film, placing the same in a developing bath comprising water, sodium sulphite, hydrochinone and formalin, rinsing, removing the ink by means of potassium bicarbonate, and-finally fixing the film in a hypo bath, for the purpose of producing a negative. V

In testimony whereof I affix my signature.

- WILLIAM HEINEOKE.