US2108261A - Method of pictorial control and material for use therein - Google Patents

Description

Patented Feb. 1

U ITED STATES I Mn'rnon or ric'roimu. common in m- I 'rnnnu. FOR USE 'rnnnnm Paul a. Jamieson. RedondoBeach, Calif.

No Drawing.

1*: Claims.

This invention relates to the art of pictorial control, as the expression is employed in the art of photographing reproduction, and pertains particularly to an advantageous method of pracgeous materials for use therein.

Pictorial control as known to photographers, consists in modifying all or a portion of a photographic register or image to obtain a resultant register which is more pleasing to the eye than the cold representation of the photographic .sub-

ject obtained by the camera lens and the photographic emulsion. For example, in portraiture, the camera lens will pick upslight defects which the eye itself would not be critical of, and these defects are observable in a photographic print principally .due to the, lack of animation in the print. Further, certain high lights and shadows might be picked upbythe camera lens which would'entirely alter .the appearance of the subject, and which, if removed, would materially improve the value of the portrait as a camera study.

Photographers have, heretofore, by working on the photographic negative in what is known as an etching process, removed portions of the silver depositby abrading the emulsion surface with a suitable implement ltoobtain a removal of highlights and have reinforced certain parts of the silver image by means of a retouching pencil to obtain a removal of shadows. This procedure is quite feasible where a relativelyiarge negative is obtained of the photographic subject, but when a miniature negative is employed, the re-touehing 35 operation is quite dificultly carried out by virtue of the fact that the detail in the negative is so small as to require the procedure to be carried out under a microscope or the like. It has been found more convenient to obtain the desired pictorial 40 control, in an enlargement made from such a miniature negative, and aqueous, solutions of iodine and potassium iodide have been employed as an-oxidizing agent toeifect a chemical convertion of silver iodide which would later be fixed out in a normal'strength of photographic hypo (sodium thiosulphate) solution. This procedure made possible, in. treating such an enlargement, 30 the removal of shadows, and the aforementioned .ticing pictorial control and to certain advantasion of a portion of the silver image byproduc-j Application September 19, 1934 Serial No. 744,670 I highlights can be removed by application of a re-touching pencil to the desired portions. L

For many subjects a color other than that of the cold neutral black of the ordinary developing papers is'desirab le, and when the color is selected principally with reference to the nature of the subject, considerable is added to theartistic efiect, and in this'connection pictorial control includes the bleaching of any desired portion of a photographic reproduction, to convert the metal- 19 110 silver deposit into an" insolublesilver salt, after which the reproduction may be immersed in a suitable redeveloping bath to develop a modified tone, at the bleached portions. As far as is known, no suitable process hasv been heretoforedisclosed which enables a bleaching operation to be carried out in a single operation, where the bleaching of but a portion of the photographic reproduction is desired. The general practice has been, heretofore, that of immersingthe reproduction in 21- 'bleaching bath whereby all portions thereof are uniformly acted upon bythe bleaching reagent, or 1 in' applying the bleachingreagent to the desired portions of the reproduction over small areas at a time, overlapping one application of reagent with a subsequent application in anattempt to secure a uniform conversion of thesilver deposit.

In the use of aqueous solutions in the above procedures, the photographic print was customarily' soaked in a very weak solution of hypo and an aqueous iodine solution was applied, as avery strong solution, to the partof the picture where the silver'deposit was too heavy. Three problems are present in the practice of,this particular method which make. it substantialiy'impossible I to obtain smooth and uniform results. First, the

iodine solution gathers in drops on the emulsion? surface and produces aispotted effect due'to the ununiform oxidation, of the silver deposit; 'Sec-' ond, due to the rapid diflusion' of the underlying 40 hypo solution, present in the print, into the iodine and because the surfacetension of the'iodine caused it to stand on the surface .of the print in irregular depths,-the iodi zing action of the iodine solution on the silver deposit would stop quicker 1 at the edge portions and'at thin portions of the iodine application than at the remaining por- 4 til-fins, which further produce'da mottling or spot- 1; g eil'ect instead of an even-removal of the silver deposit. Third, the iodine solution would have a area in an irregular nianner, thus-making the removal' of small'areas of silver diiiicult. In addition to the above causes f nomunii'orm results in an etching procedure, it been found that the reinoval of the silver deposit is best obtained in "only a single application of the iodine reagent.

in view of the fact that after an application'of anaqueous iodine solutionca not inconsiderable amount of sodium iodide is formed as a reaction product, which acts both as an accelerator in a subsequent application and as a gelatine swelling agent, so that if a second application of aqxuteous iodine reagent is made to a particular no ion of the negative a highly localized actionis obtained which invariably causes an irregular outline to result. It isthus considered necessary, with the use of aqueous iodine etchingreagents, to so gauge a single application that the desired etching is obtained without requiring a second applicationI and it will be appreciated that such a procedure part of the operator in view of the fact that substantially every type of photographic emulsion requires 'a diflerent treatment and time of application.

In addition v use of aqueous iodine solutions in pictorial com trol, it was found that only a small amount oi work could be done on a print at a given time due to the swelling of the gelatine in the emulsion due to the action'of. the formed sodium iodide and, further, considerable dimculty was offered by the uncontrollable change inthe hypo content of the emulsion during repeated applications or the iodine solution to a particular area in the print. One of the particular objects of the present invention is to prcvide a method of pictorial control which provides for easy and accurate removal of 7 any deliredportion of a silver image, under conditions of precise controlofthe-size. of theatres under treatment, and of the reduction of the intensity of the silver image over the, desired area; .A further object oi'the invention is't'o provide a method of'pictorial control which does notcause a serious swelling of the gelatine and which maybe practiced for relatively long periods of I ditionew time onzany particular area or"which may be interrupted at any time and continued at a later time without, damage or deterioration of the photographic'surfaoeorimaae. c

A object of the-invention is to provide a method of pictorial control employing a pinrality oi successive applications of an'oxidising agent, in which each application of such agent is comparable to another application, whereby the eifect of one or more applications can be anticiand thedesired bleaching of the silver deposit obtained without danger of over-bleaching of any particular area. v A further object of the inventionis to provide a method o! pictorial control which maybe practiced in of large areas of silverdeposit or in the uniform reduction of the intensity of ofsilve'r deposit-under controlled conobiect or the invention isto provide certain reagents'foruse in the present method of pictorial, control. in which theaetionor'eflectivenesa-o! agentis iixed and predictable.

object of the inventionis to provide a silvereaTdiiihfagent in a hon-aqueous base or whereby the application of such agent t a,1oa,a'e1 tendency to run or creep beyond the application uires tremendous experience on the to the above disadvantages .in the between the etching and bleaching techniques is.

that in the etching'technique the metallic silver deposit is chemically acted upon in the production of a soluble silver salt which is continuouslybrought into solution within the emulsion layer as rapidly as it is formed, while -in the bleaching technique the metallic silver is converted to a .silver salt. which is allowed to remain in place,

after .which the print may be re-developed to obthe event that it is desired to preserve the bleach.

In carrying out the etching technique, a suitable control medium is applied .to the print or negative over the entire area to be worked upon causing excessive swelling or softening. This control medium is preferably" one having a pronounced neutralizingaction on free iodine and a solvent action on silver iodide and in addition, provides some neutralizing ac tion tollmit the extent oi penetration and diffusion of the iodine reagent. Furthermore, this control medium is preferably one having a low vapor tension so that the dampened print will remain in the desired tain a modified tone or fixed out with hypo in v to obtain a partial hydration of the gelatine by providing a small amount of moisture without moistened condition for arelatively-long period.

After the application of the control medium, a' non-aqueous solution of \iodine may-be applied.

by means of a brush or a tuft of cotton directly to the portions of the i e to be wholly or partly removed, "allowed to stand for a short period,- for example, from one-quarter-second to one minute,

and the control medium is then applied to the treated area-to stop the action oi the non-aqueous iodine solution and dissolve the formed silver iodide. The non-aqueous iodine solution may be added in any desired numberof separate steps,

whereby a slight reduction in the intensity of the silver-image is obtained at eachstep, but the re-- duction will reach a maximum after a limited number of such applications, or, if the operator is suficiently experienced with the manner in which the iodine solution acts upon the particular type of surface with which he is engaged, the desiredremovalof the silver deposit may be obtained in a single-application. After the desired removal of the various portions of silver image is obtained, the print may be then fixed was an acid hypo bath, washed, and dried in the usual man ner.

Whenthe bleaching technique-is practiced, the non-aqueous iodine solution maybe distributed evenly-over the area to be bleached, being, soplied directly to a thoroughly dry print or negative. The distribution of the-iodine solution over the photographic surface-may be by spreading the same with a tuit of cotton. I Due to the absence of water, the iodine solution will have no bleaching eiiect-upon the silver deposit at this step of the operation, ambit will be appreciated that the reagentmay be applied as carefully .ao desired and asslowly asdesired'. so that only the particular areas to be bleached are coated.

In the event that certain areas are inadvertently ably only slightly aqueous so that there will be no tendency for water from this solution to permeate the gelatine beyond the edges of the area to which this solution is applied and thus cause an undesired bleaching at these portions of the photographic image. -When the desired areas of the photographic image have been covered with the iodine solution to the desired extent, the photographic print or negative may then be immersed in a water bath whereupon the diffusion of the water into the emulsion will enable the iodine to react with the silver deposit in the production of silver iodide and the removal of metallic silver. The print may be allowed to remain in the water bath until the desired bleach is completed, whereupon it may be removed to a photographic fixing solution, washed, and dried, or maybe placed in a warm tone developer. or the like, to produce a different tone or color, and then handled in the customary manner for finishing.

- Instead ofimmersing the photographic reproduction in a water bath to obtain the desired activation of the non-aqueous iodine solution, the reproduction may beexposed to a steaming opera tion, whereby the necessary quantity of moisture may be absorbed by the emulsion and the reaction between the iodine'and the metallic silver made possible, and this procedure is advantageously em-- ployed where it is desired to carry out the bleaching operation in a series of two or more steps, in view of the fact that after the steaming operation the reproduction will be in substantially dry condition 'so that a second application of the nonaqueous iodine solution may bemade to the desired portions thereof without waiting a relatively long period for the same to dry. Itha's been noted that when the activation of the iodine is obtained through the use of steam, certain slight discolorations of the print will occasionally befound, which are very possiblydue to the formation of certain calcium salts, but these discolorations may be easily removed by subsequent treatment with a potassium metabisulphite solution.

The control medium above described in connection with the etching technique, is a partly aqueous solution of an agent capable of neutralizing the iodine present in the non-aqueous solu- 7 tion and an agent capable of causing-solution or removal of the silver iodide formed by reaction between the iodine agent and the metallic silver deposit. This medium also contains an agent which, restricts the absorption of water by the gelatine, and thus limitsthe extent of swelling of the gelatine. This latter agent is preferably one which has a lower vapor pressure than water so .that it will not evaporate from the emulsion at;

such a rate that the proportion of water remainwater present in this solution controls the degree of softening of the gelatine of the emulsion, which in turn controls the speed of reaction of'the iodine agent ,on the silver deposit. Other materials or solvents are incorporated in the control medium (d) A material which facilitates penetrating power on gelatine.

for the purpose of modifying its surface tension so that the subsequently applied non-aqueous iodine solution will neither puddle nor spread unevenly and, further, provide for easy access of the iodine neutralizing agent to theiodine through the non-aqueous medium carrying the iodine in solution. In other words, the control medium, while it must be at least "somewhat aqueous in order to suitably prepare the emulsion for the action of the non-aqueous iodine solution, must also be capable of promptly reacting with the non-aqueous iodine solution in a neutralizing action.

The constituents of this control medium may be divided into the following general classes:

(a) A material'having a neutralizing action on elemental iodine Hypo; thiourea (b) A material having a solvent action on silver iodide"--- Hypo; thiourea (c) A water soluble liquid material-having the property of controlling the swelling action of water on gelatine and a vapor pressure lower than water Carbitol the transfer of iodine from non-aqueous to aqueous solution phase Hexalin (e) Alcoholic solvents L Isopropyl and butyl alcohols, glycols.

I have determined that a 50mm of the above materials in certain preferred proportions, .pro-

vides a very satisfactory control medium having the above-described important properties. A typical example of the fo'rmula of a control me- In the above formula, the boric acid functions to prevent precipitation of calcium iodide when the nonaqueous iodine solution is applied. The

hexalin serves a rather peculiar function in that it facilitates the transfer of iodine from its nonaqueous dissolved condition in' the subsequently as a resinous material, for example, rosin or balsam, for modifying the consistency and coagulating properties of the solution, soluble iodides mthe emumon mcreasei The amount 01/ for increasing the solubility and activity of the iodine, certain alcohols to assist in the solution water, and anon-aqueous agent having some of the'io'dine and for obtaining'a balance with respect to the, miscibility of the solution with i into the following general classes:

(a) A silver-oxidizing agent Iodine (b) Accelerating agents for the iodine Oil soluble i n organic iodides '(c) Consistency (viscosity) modifying agents Rosin and castor oil (d) Oleaginous iodine solvent Rape seed oil (e) Non-gelatine-swelling agents,

having a partial solution effect on iodine and iodides and serving to assist the conversion of the iodine and iodides from non-aqueous to aqueous solution phase Alcohols and hexalin (f) Solvent material having the same properties as the alcohols, but in addition having apenetrating action on partially hydrated gelatine Die t hylene glycol (g) A solventimaterial having the property of regulating the .solubility of iodine and the iodides with respect to the non-aqueous and aqueous solution phases A liquid hydrocarbon (kerosene) A typical formula for the non-aqueous iodine solution may be as follows:

Rosin (or balsam) grains Iodine poundn 1 Calcium iodide grains 400 Potassium iodide do Normal butyl alcohol ii. 02.. 10 Fusel oil (amyl alcohol) do 5 Castor oil do 2 Kerosene do 14 Rape seed oil do 20 Diethylene glycol do 2 Hexalin do '7 In the above formula the rosin and castor oil act to modify the consistency of the solution; the butyl alcohol, fusel oil, kerosene, rape seed oil, and hexalin act jointly to effect solution of the iodine, the kerosene acting particularly in assisting the distribution of the iodine between the non-aqueous iodine solution and the dampened emulsion, serving principally to assist the -difiusi0n of such iodine from its non-aqueous phase into aqueous phase, and thereby materially controlling the speed of reaction of the iodine solution on the emulsion; the calcium and potassium iodides act to increase the solubllity and activity of the iodine (calcium iodide being used principally by reason of its greater solubility in oils than potassium iodide and its lower gelatine softening action); and the diethylene glycol is employed principally as the limited softening agent for the gelatine. The kerosene appears'to act to limit the solubility of the iodine and iodides, so that the non-aqueous iodine reagent contains iodine in a concentration approximatelyequal to the saturation solubility of iodine, so that the iodine is just on the verge of precipitation from-solution, whereby the transfer of iodine from non-aqueous phase to aqueous phase is facilitated where it may react with the silver deposit when brought in contact with the dampened emulsion. The kerosene thus serves to maintain the speed of reaction of the iodine non-aqueous iodine solution with a suitable modifying solvent whereby the activity thereof will decrease with its penetration into the emulsion. This thinner may be employed in substantially any ratio to the iodine solution and serves to decrease the total action of the iodine solution in direct ratio to the dilution employed, without materially modifying the reaction rate of the iodine solution. A typical formula for the thinning medium is as follows:

Fl. oz. Hexalin 18 Carbitol 2 Kerosene 5 In the above formula the hexalin functions as a solvent for all of the constituents of the non-aqueous iodine solution so that an adequate dilution or thinning is possible and the carbitol serves principally to restrain the swelling of the gelatine. The kerosene serves to preserve the distribution balance of the dissolved iodine and iodides so that the reaction rate of the solution is not materially modified upon dilution.

The neutralizing medium referred to in connection with the bleaching technique above described, may comprise a partly aqueous or nonaqueous solution of a reagent adapted to completely vitiate the oxidizing power of the iodine.

' As above stated, the water content of this solution should be relatively small, so as to prevent undesired bleaching adjacent theedges of the area to which this solution is applied. Also, the solvent or solvents employed therein should have a sufficiently low vapor pressure to substantially prevent or minimize evaporation therefrom during' application. Excessive evaporation of solvent would not only alter the consistency and concentration of the solution, but might cause suiiicient cooling to result in condensation of water in contact therewith, which would be objectionable. A typical formula for this neutralizing medium is as follows:

Fusel oil fl. oz

1 Hexalin do 1 Tniourea grains 50 Tri-ethanolamine drams Butyl alcohol do 2 Water (this may be omitted, if desired) do 2 In the above formula, the tri-ethanolamine acts to increase the rate of absorption of the' lution, substantially immiscibleor only slightly miscible with water, and containing a reagent careful government of the degree of reactionmay be obtained. In the present description the expression "silver deposit will be understood to designate either metallic silver or silver sulfide, in view of the fact that the present method and reagents are equally applicable to use on these two types of silver deposit. To my knowledge, in ,all previous attempts to obtain photographic reduction for pictorial control through the agency of a material which ischemlcally capable of reacting with silver deposit, the material has been employed in aqueous solution, in which case the material started its action .upon the silver immediately upon being placed in contact therewith, and the'only control possible was by applying the reagent in small amounts, over small areas and then quickly fixing or washing the print. In general the chemical reaction necessarily progressed until the reagentwas consumed by its reaction, or until the print or negative was immersed in a fixing or washing solution, or oth-- erwise treated with a reagent having a neutraliz deposit immediately after its application, and .went the full depth of the emulsion practically instantaneously, whereby no control of the re-. action was possible other than by a control of the quantity applied over a "given area, and when a relatively large area had to be covered, the areas -flrst covered would be subjected to somewhat fled by previous applications. In the bleaching technique as provided by the present method, the entire dry surface of the print or negative maygreater or at' least somewhat advanced treatment before the latter areas were properly covered, and very ununiform results were obtained. The present process; as applied to etching technique, permits one tooperate on any particular isolated, area in a series of successive applications of the reagent, which applications are alternated with applications of a control medium which definitely pre-" serves the absorbent characteristics of the gelstine and removes the excess oxidizing reagent between applications thereof so that each application is in eflecta fresh application unmodibe covered with the then inactive oxidizing agent, and the actual bleaching reaction caused to take place when the entire area to be bleached has been covered to the desired extent.

- It will be comprehended that the present invention is not limited to the practice of pictorial control on negatives alone, nor on prints alone,

treatment-Lo! .both types. of emulsions. 1"ur thermore, though I flnd'a wide application of my invention to the treatment of enlargements from the so-called miniature" negatives, i. e., negatives made with small cameras, the invention is also, applicable to the practice of pictorial control directly to any photographic print or negative, or to motion picture negatives or positives.

I claim:

1. In the art of photographic pictorial control, the method of, treating a silver deposit in a gelatine emulsion, which comprises: separately applying to such an emulsion a non-aqueous iodine solution containing an oleaginous iodine solvent, and an aqueous medium for controlling the hydration of the gelatine in such emulsion, and

subsequently subjecting said emulsion to a pho-' the absence of water, and said at least partially aqueous medium serving to at least partially hydrate the gelatine of said emulsion whereby said iodine chemically reacts with said silver. de-

posit in the formation of a silver salt. 1 i

4. The method setforth in claim 3,,said at least partially aqueous medium being applied to said emulsion prior to the application of said non-aqueous iodine. solution.

5. In the art of photographic pictorial control, the method which comprises: applying a partially aqueous solution to a photographic emulsion containing gelatineand a silver deposit to obtain apartial hydration of saidggelatlne: applying a non-aqueous solution of i dine containing an oleaginous iodine solvent to'said partially hydrated emulsion to cause oxidation of said silver to a salt of silver, and then removing said silver salt from said emulsion.

6; In the art of photographic pictorial control, the method which comprises: applying a nonaqueous iodine solution containing an oleaginous iodine solvent to the surface of a substantially dry photographic emulsion containing gelatine and a silver deposit; applying an aqueous medium to said emulsion to eflect an at least partial hydrationof the gelatine in said emulsion to cause a reaction between said iodine and said silver deposit in the production of a silver salt; and subsequently treating said register in a finishing operation involving. the chemical fixation of said silver salt.

'7. The, method set forth in claim 6, said aqueous medium comprising water vapor applied to a compound chemically inert with respect to metallic silver; and a non-aqueous alcoholic liquid having a vaporpressure' lower than that of water and having the property of restricting the absorption of water by .the gelatine in said emulsion.

9. A photographic pictorial control'solution for use on a photographic surface provided with an. i v

emulsion comprising gelatine and a metallic deposit or silver or the like, which comprises: wa-

ter; a water-soluble reducing reagent adapted to react with elemental iodine in the formation of a compound chemically inert with respect to metallic silver; and a water-soluble ether having a vapor pressure lower than that or water and the property of restricting the absorption of wa- Sodium thiosulphate grains 125 Thiourea do 75 Boric acid do 15 Water il. oz 4 Isopropyl alcohol do 2 Carbitol do 3 Hexalin (hexahydrophenol) do 1 Diethylene glyr'nl do 2 Glycerine -do 1 Normal butyl alcohol do.. 1 a

ter by gelatine, said ether .being present in an amount sufilcient to prevent an appreciable soitening .of the gelatine in said emulsion by the water present in said solution.

10. A solution for use in photographic pictorial control; which comprises: water, sodium thiosulphate, thiourea, an alcoholic solvent, and a water soluble ether having the property 01 restricting the absorption of water by gelatine.

11. A solution for use in photographic pictorial control, which comprises:

12. A solution for use in photographic pictorial control which comprises: a non-aqueous soluti'on of iodine in a plurality of solvents, at least one of said solvents comprising an oleaginous liquid, and another of said solvents comprising an alcoholic liquid at least partially miscible with water. x

13. A solution for use in photographic pictorial control, which comprises: iodine, a non-aqueous oleaginous solvent for iodine, a water-miscible non-aqueous alcoholic solvent for iodine, and a second alcoholic liquid agent having the property of penetrating partially hydrated gelatine.

14. A solution for use in photographic pictorial control, which comprises: iodine, a non-aqueous oleaginous solvent for iodine, a water-miscible non-aqueous alcoholic iodine solvent, an oil-soluhle inorganic iodide, a soluble resin, and a sec-,

ond alcoholic liquid agent having the property of penetrating partially hydrated gelatine.

15. A solution for use in photographic pictorial control, which comprises:

16. A solution for use in photographic pictorial control, which comprises: a'water-soluble reducing reagent adapted to react with elemental iodine in the formation of a compound chemically inactive with respect to metallic silver; an alcoholic solvent for said reducing agent; and an alcoholic liquid having mutual solvent properties with respect to water, iodine, and oleaginous materials.

17. A solution for use in photographic pictorial control, which comprises:

Fusel oil ..'....ii. 02.. 1 Hexalin do 1 Thiourea grains Tri-ethanolamine drarns 2 Butyl alcohol do 2 PAUL H. JAMIESON.