US1484029A - Multiple-step process of photographic reproduction - Google Patents

Description

. Patented Feb. 19,. I I

UNITED STATES PATENT org-ice.

ROBERT JO HN, OF NEW YORK, '11. Y., ASSIGNOR TO DAY LIGHT FILM CORPORATION, A

conromrrroiw or NEW YORK.

MULTIPLE- STEP PROCESS OI PHOTOGRAPHIC REPRODUCTION.

m matin Application filed October], 1919. Serial No. 329,078.

To all whom it may concern: opaque,- translucent, or transparent, but

Be. it known that I, ROBERT JOHN, a preferably is mounted on a transparent carcitizen of the United States, residing at rier such, for example, as glass or a cellulose New York, in the county of New York and base, in order that the silver salt emulsion State of New Yorlr, have invented a certain may be exposed to the modified light through its transparent carrier."

new and useful Multiple-Step Process of- Photographic Reproduction, of which the following'is a specification.

My invention relates to a multiple step The emulsion then is treated by a developand hardening process comprising a of steps so that the emulsion can plurality process of photographic reproduction and beexamined at an intermediate stage or 05 has ,for its object to produce a printing surface containing a photographic record of. lights and shades from which copies can be made by a dye or ink cont-act transfer recess. An illustrative dye contact transer process is disclosed in patent to Shep-' herd andBartlett, No. 728,310, granted May 19,. 1903, for photographic printing, and an illustrative ink contact transfer process is disclosed in Cassells Cyclopaedia of Photography, Cassell & Co, New York,

' 1912, at page 124, under the title Collotype,

it being understood, however, that theprocesses thus illustrated do not use a printing plate having-the novel and beneficial characteristics of the printing plate disclosed herein. Although the preferred niethod is to obtain the photographic record for the printing surface. from a completed negative, it may be obtained *by direct exposure, as, for example, in a camera, the details of which method are disclosed in a copending application for Letters Patent Serial No. 327,890, filed October 2, 1919, for process of photographic reproduction directly from a negative. The printing surface when treated with dye or ink also maybe used in the same manner as a positive,-either for direct view,'.or with reflected light, or with transmitted light as in a projecting machine.

The invention. is applicable to monochromatic,-' poly chromatic, or natural color photography 'both in still photography and in motion picture photo raphy. The term color,is intended to inchide-blaok, which sometimes technically is designated as an absence of color.

. negative which it is desired to reproduce. The sllver salt emulsion-may be earned or mounted on any desired support, either.

stages and the remaining step or steps adapted to produce with great certainty the J are removed in any desired manner, as for example, by melting with warm water. The result-of the above treatment is the production of. what may be termed a print ing surfare having novel characteristics and beneficial properties never before attained.

The most importanflof-the novel characteristics is -a printing or reproducing surface comprisingranules or great numbers of photographiea ly formed, extremely minute, individual protuberances which are distributed and grouped irregularly so as to represent photographic lights and shades.

The most'important of the beneficial properties is that such a rinting. surface when treated with a dye, ink or other coloring matter, will absorb or take up or carry the coloring matter within a few seconds,

and when thus treated and placed in con- 'tact with a substance which is to carry the final reproduction such. for example as a gelatin, will give up its coloring matter practically instantaneously and produce on said gelatin an exact and perfect reproduction. This speedy result, which is novel and was impossiblef of attainment before the present invention, is ofprime importance in the production of motion picture positives from motion picti'ire"negatives.'

although the saving of time and the superior results obtainable in still photography also are important. The printing plate or film, moreover, when treated-with coloring matter, may be used as a positive if reproductions are not desired.

For purposes of illustration, a two tep process'will be described, the first of w Y changes the light-affectedsensitiz ed par-.

ticles to metallic silver and partially hardens the emulsion adjacent each particle, and thetion containing a hardening or tanning agent the effect of which is controlled and limited selectively by the presence of varying quantities of a neutralizing agent is as 2 follows Water, 8.5 ounces.

P rogallic acid, 11 grains.

etol (monomethylparamidophenol sulphate), 9 grains. 1

Potassium bromide, 4: grains.

Sodium carbonate, 200 grains. ,Sodium sulphite substantially over 60 to 80 grains. (v

In theabove sample formula the harden ing or tanning agent is pyrogallic acid,

and the controlling and limiting agent is sodium sulphite which may be varied in amount selectively within limits to obtain the desired result. It is well known that pyrogallic acid also is a developing agent andthat sodium sulphite is a preservative adapted to prevent oxidation of the pyro: galhc acid in solution. Other hardening and tanning agents and other neutralizing: agents may be used, the' above formula representing one developing solution by which the process may be carried out. The main difference between the above sample formula and standard developing formulas 4 is in the amount of sodium sulphite used.

In standard formulas the amount of sodium sulphite used is -so greatly in excess of the amount used in the above sample formnlathat the tanning or hardening ef-- 5 feet of the pyrogallic acid is entirely neu-' Qtralized or overcome. In the sample for- 1nula,the sodium sulphite merely controls and limits the hardening effect of the pyrogallol. It is of course understood by those skilled in the art that when a thick layer vof emulsion is treated, or when the exposure is through the transparent carrier, it is advisable, in order to accelerate the action of the pyrogallic acid, to use larger quantities of an accelerator such, for 'example, as *sodium carbonate or its equivalents than when the emulsion layer is thin or exposed on its face. When larger quanties of sodium carbonate thus are used, it

95; is necessary to increase the amount of so- Meaeae dium sulphite. The above safnple formula body the selectively controlled hardening agent in the developer solution, it maybe used separately if desired, by such modifica tion of the developer solution as will pre vent such a hardening. of the emulsion as will prevent the selective hardening desired.

It is believed that the hardening ortanning effect of the pyrogallic acid exerts its action first adjacent the so-called latent image, or in other. words, on the portions of emulsion adjacent the particles of silver salts affected by the exposure light and converted by the developer into metallic silver. Thus in a silver bromide film, the throwing ofi of the bromide from a light-affected silver bromide particle in the developing process, probably reacts with the pyrogallic acid to harden or tan or render insoluble or unremovable the adjacent emulsion. Thus in the embodiment chosen for purposes of illustration, the reaction roducts from the chemical effects of the eveloper solution, are believed to react with'the selectively controlled hardening agent. The essential resultis a partially hardened emulsion surface correspondin to'the lights andshades to be reproduced. By controlling the hardening or tanning effect of the pyrogallic acid as above a set forth, only the particles of emulsion adjacent the said'light-afl'ected particles of silver salts are hardened, the relative proportions of the hardening agent (whether or not accelerated by an accelerating agent) and.

of the neutralizing agent being such as to control selectively the effective area of influence of the hardening agent. It'is preferable that only those portions of emulsion be hardened which'are adjacent the carrier for the emulslon, which may be accomplished in various ways,'some of'whlch are .dlsclosed in my copending applications for Letters Patent Serial No..313,239, filed July 25,1919, for a thin mounted sensitized emulsionp Serial No. 313,240, filed July 25, 1919, for process of making a contact transfer printing surface by complementary light; Serial No. 327,891,'fi1ed October 2, 1919, for otassiu-m iodide formula for photograp ic processes, process of using same, and article obtained thereby; and in my Patent No. 1,453,258, dated April 24, 1923, for process of making a contact transfer printing sur- 130 ited selectively by the nor, as, 'for example, by

35 water.

1 tities of a neutralizing agent is as treating solution face with a colored emulsion, and among which may be mentioned the exposure of the sensitized emulsion through its transparent carrier and the limitation of the depth to 5 whiclr the rays of exposurelight penetrate "by having the actinic rays of the exposure light and the emulsion complementary in color. y

The partially hardened emulsion preferably then is fixed to remove the unreduced silver salts.

As the sensitized content of the partially hardened emulsion has been changed to me'-- tallic silver by the action of the developing solution, the complete hardening of the .emulsion. can be accomplished by treatment with a hardening solution which reacts with metallic silver. As the emulsion can be examined at this intermediate stage of hardening it is 'possibleto vary the process of complete hardening to obtain with great certainty any desired printing surfaces.

The second step oi the embodiment chosen for purposes of illustratibm-comprises treating the partially hardened emulsion with a solution containin an agent which renders completely insolu 1e or unremovable the emu sion adjacent its metallic silvercontent, the efiect of which agent is controlled or limresence of varying quantities of a neutra izin agent, after which the soluble or remova le portionsof emulsion are removed in any desired manmelting with warm mate, and the controlling and limiting agent is sulphuric acid which may be varied in amount selectively within limits to obtain the desired result.' Other hardening and tanning agents. and other neutralizing 5 agents may be used, the above formula representing one treating solution b which the process may becarried out. ydrochloric acid, for example, as well as other acids may be used, the above formularepresenting one b which the process may be earned out. The tanning or hardening effect of potassium bichromate on the emulslon surrounding a metallic silver .was known previous to my invention, but the method of controlling the tanning or hair}.

ening effect so that a too contrasting or paddy relief was obviated and the desired granular printing surface'obtained was not known previous to my-invention; Thus if potassium bichromate without any sulphuric acid or with only a very little sulphuric acid is used. to treat metallic silver in an is so great that a too'contrasting or paddy .relief is obtained. As more acid is added, however, the relief becomes thinner until the point is reached where the amount of acid added produces a relief characterized by the granular printing surface desiredf If acid p is added beyond this point, the tanning or hardening effect of the potassium bichromate 'willbe neutralized entirely so'that all the emulsion, the tanning. or hardening action emulsion would dissolv e from the carrier when treated withwarm water.

It is believed that the hardening or tan? ,ning effect of the potassium bichromate exerts its action first adjacent the particles of metallic silver. The potassium bichromate probably reacts with the metallic silver to throw oil products of reaction which harden or ten or render insoluble or unremovable. the adjacent emulsion; The essential result is a hardened emulsion surface corresponding to the lights and shades to be reproduced which acquire and give up any desired color in a comparatively short. time. '-By controlling the hardening or tanning effect of the potassium bichromate as above set. forth, only the partlcles of emulsion adja' cent the said metallic silver are hardened. The unhardened portions, as stated above, then may be removed in any desired manner as by placing-theemulsion in warm water which causes the unhardened or soluble portions to soften and melt away from the hardened or insoluble portions so that the hardened emulsion alone will remain in the form of extremely minute, individual protuberances which are, distributed and grouped irregularly so as to represent'the hotographic lights and shades which it isesired to reproduce. It ris preferable that only those portions of emulsion be hardened which are .adjacent-the carrier for the emulsion, which .may be accomplished in various ways, some bffwhich are disclosed in my Patents, Nos. 1,374,853, dated April 12, 1921 and 1,417 ,328, dated May 23, 1922 in my copending applications forLetters PatentSerial Nos. 327,- 889, filed October 2, 1919, 327,890, filed October 2, 1919, 313,239, filed July 25, 1919 and 313,240, filed July 25, 1919, and amongv which may be mentioned the exposure of the sensitized emulsion through its transparent carrier and the limitation of the depth to which the rays of exposure light penetrate by havin the actinic rays of the exp0$ re light an the emulsion complementary in color. I v 1 Although the treating solution referred to acts also as a bleach, the hardened emulsion may be bleached further if desired to remove any black metallic silver not already bleached. Thismay be done in -well known manner and while not necessar is of advantage as it enables the operator to watch the effect of the coloring matter on the printing surface to which it is applied for carrying out the printing process.

The order of melting, bleaching, and fixing is not important and may be carried the action of the desired coloring matter as by placing it in or carrying it through a 4 liquor color bath. The colored surface then is placed in contact, preferably under some pressure, with the substance on which the positive .is' to be made, as by a roller or by a s ueegee. As stated above, the printing sur ace prepared by my process receives and gives up the coloring matter almost instantly as distinguished from other processes which take an appreciable length of time.

Natural color effects may be produced in well known niannensuch for example as by exposure through color screens with subsequent treatment and manipulation to obtain the desired results. I

Many modifications of my invention will be apparent to those skilled in the art withoutdeparting therefrom or from the scope of the claims, my invention not being limited to the embodiments thereof chosen for purposes of illustration but consisting of a aaeaota g v r process for forming a-printing surface capa- 40 ble of acquiring and giving up a desired color with greatrapidity by treating an emulsion by a multiple step process which hardens the emulsion to correspond to the lights and shades desired to be reproduced.

invention, what I claim is: 7

1. The processof forming a photographic record of lights and shades capable of use as a transfer printing plate, which comprises developing an exposed photographic emulsion with a partial-emulsion-hardening solutionand then hardening portions'of emulsion adjacent the light affected sensitive con:

45 Having described one embodimentmf my tent of the emulsion with an agent adapted to harden said emulsion by reaction with the light affected sensitive content of the emulsion, and with a neutralizing agent for said hardening agent, the relative proportions of said hardening and neutralizing agents be- 00 ing such as to control selectively the'eifective area of influence of the hardening agent 0 but to an extent less than the complete neu-- tralization of said hardening agent.

2. The process specified in claim 1 in 85 which the hardening agent is potassium bichromate.

3. The process specified in claim 1 in whiich the neutralizing agent is sulphuric aci y y 4. The process specified in claim 1 in which'the hardening agent is potassium bichromate and the neutralizing agent issulphuric acid.

- In testimony thatli, claim the foregoing,

I have hereunto set my-hand this 2nd day of ()ctober, 1919. 1 ROBERT JOHN;