US1600736A - Art of light-sensitive photographic materials - Google Patents

Description

' therein n very small amounts.

Patented Sept. 21,1926.

U N i S T Banner: 1*. runnnr'r, or GREECE, NEW Yon' Assieivon .ro nAsr An' KODAK comram,

OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

ART or nronr-snnsrrivn rnorooaarmoiun'rnnmrs.

Ho Drawing.

' This invention relates to the art ofphotographic materials.

One object of the invention is to provide photographic sensitizing materials capable of greatly increasing the light sensitiveness of photographic emulsions especially of the developing-out type, even when incorporated Another obto provide such materials in concenject is and sufficiently purified conditlon so trated stances in which they are mixed. A still to give density incorporated therewith.

f further object is. to'provide a process for obtaining said material in said desirable condition.

Another, object of the invention is to provide photographic emulsions such as devel-' oping-out emu'lsions,'having new and improved properties because'of'the use or presence therein of my independent sensitizing vmaterial. Still another object of my invention is to provide a processin which my said sensitizing material is used to improve v photographic emulsions, especially developing-out emulsions. as regards light sensitivenes's, by which term Iinclude their ability to 7 give the earliest visible impression or image with the minimum exposure or their ability after a given exposure or both, the usual photographic fluid treat: ments. being used in preparing such impression or'image. L

A further object of the invention is to provide a colloid product, such as treated gelatin, the usefulness of which for forming light sensitive photographic emulsions; notbly developing-out ones, is increased" and controlled by my said sensitizing material Another object of i the invention is to provide a corresponding process for making said intermediate colloid product.

Other objects are,-to increase the sensitiveness of photographic emulsions, particularly developing-out emulsions, while wholly or partially dispensing with expensive or long and uncertain so-called ripening methods;- toenable the use of a type of gelatin having. desirable physical qualities inmaknessof photographic emulsions, particularly Application filed June 6, 1924. Serial No. 718,409.

developing-out ones, the grain characteristics of which have already been determined; to increase the general light sensitiveness of such photographic emulsions throughout the spectral ranges to which they are normally sensitive; to make such photographic emulsions of standard light sensitive characteristics with gelatinswhieh normally do not produce emulsions having such characteristics; to make, as intermediates in the manufacture of photographic emulsions, gelatins of standard light sensitiveness giving power out of gelatins which do not normally have the power of giving such standard sensitiveness to emulsions, such as developing-out ones made from them. Further objects will hereinafter appear. r j

I have found a photographic sensitizing material, very small amounts of which greatly, increase the light sensitiveness of photographic emulsions, such as those, of the developing-out gelatino-silver-halide type, for example. This material I have found out how to obtain in concentrated forms, so that when incorporated in such emulsions or gelatins for such emulsions, it produces its sensitivity-increasing action without harmfully diluting said emulsions or gelatins, or impairing thephysical properties of them. In other word s, the use of my sensitizing material furnishes a safe, practical,

and largely independent way of controlling the properties of emulsions in addition tomy invention in connection with such emulsions; but it will be understood that my invention is not restricted to this example except as indicated in the claims.

The first operation. in practising my inventionis the preparation of the sensitizing material. Be ng of biochemical origin, it is preferably concentrated, or separated from the organic tissues, or bulky products from such tissues, with which it is associat ed. For example, it originates in the tissues that yield gelatins and is carried into the latter during their manufacture. Such 'gelatins especially those. prepared for photog'raphic use, are, therefore, useful sources fromwhi'ch my sensitizing material may be derived. Not-all gelatins contain it to the same extent. Totest whether any particular kind or available batch 'of gelatin will be a sufiiciently fruitful source of sensitizer, a small sample of it can be extracted by the method hereinafter described and the ex tract added to an emulsion, such as the one hereinafter disclosed. If the sample sensitizer causes a. good increase in light sensitiveness of the emulsion, then the kind of gelatin or whole batch of it can be extracted. This extraction of a sample and trial in a known emulsion provides a ready test of the raw material; but'in the absence of test,

practically any gelatin which can be used 1 out the invention, water.

' preferably distilled-is added to the gelatin at a moderate temperature, say 85 F, for instance. The amount of water 1s conveniently in aslight excess (say 10 to 20 per' cent) over the amount absorbed by the gelatin to swell it. at said working temperature.

\ 1101 as a preservative.

This is allowed to stand or soak at said temperature fv r several days, two or three being usually 'su cient. During this time evaporation should be lessened or prevented, such as by keeping the wet gelatin in a closed vessel. Harmful bacterial action can be prevented by adding a small amount of phe- Agitation of the wet gelatin during the soaking is very desirable. Vigorous shaking of it at intervals in the vesselwhichcontains it is one satisfactory way of doingthis;

At the endof the soaking period, the encess watery solution, which is often somewhat viscous,can be poured off from the gelatin.- The yield is improved if some of the liquid also bepressed out of the gelatin,

say by centrifuging it. The liquid, which hastakeitup the necessary substances from Y the gelatin,' constitutes an excellent sensitizing material. Water may,, however, be evaporated from it, making .it still more con .centrated, such evaporation beingconducted during the soaking, or afterward, or both. The ultimate paste, and even the substantially dry material, reached by. continued drying, likewise constitute concentrated sen- .sitizing materials. Such materials are, in

general, almost-colorless. There are'usually' 3 some breakf'dow nproducts-of gelatin in the materlal whetherthe latter. be aqueous or dry; but it is substantially free from unhydrolyzed gelatin. The sensitizing materialv is, therefore, for all practical purposes, freed from the bulk of organic tissues and their bulky derivatives, such as gelatin, with which it was initially associated. Stated in another way, the proportion of active sensitizing bodies in the final material is larger than they proportion .in the sources from which it is prepared. This makes it especially useful because it can be incorporated into emulsions without undesirably diuse less than 100% excess "of liquid. But instead of using onlya small excess of water during the soaking, a large excess may be substituted and when the resulting dilute liquid is poured off from the soaked gelatine, it may be concentrated by removal of enough water until it gives a sufficiently strong sensitizing action. It withstands boiling butis preferably concentrated below boiling temperature at either atmospheric or reduced pressure. After evaporation to substantial dryness, the residue may be again taken up in waterwith the sensitizing property still present. Investigation indicates that theaqueous solution is not a true one but is colloidal. The fact that the sensitiz: ing propertyremains in the dry residue and in the aqueous solutionshows that the sen sitizing material has a very useful stability. It is generally neither markedly alkaline nor acid although it withstands both dilute acids and alkalis' and can be used with them in making emulsions.- I classify it as organic or biochemical in distinction from inorganic material such as ammonia, silver nitrate, etc., for example; While it keeps Well,

bacterial action can be prevented by a'little- I sions-or in colloids for emulsions orboth.

It gives; additional light'sensitiveness to various kinds of emulsions having different speeds and other distinctive characteristics.

While it may be added at'diiferent stages of emulsion manufacture or be mixed with emulsion ingredients, either organic or inorganic, before theyare mixed into the emula sion, nevertheless it can be very conveniently mixed into the emulsion when the latter is complete, ready for coating. With the grain characteristics, such as size d1stribution,ietc.,

properties by ace-73c already determined, and the other physical and photographic properties of the emulsion already taken care of at this stage,,I can practical independently increase its light sensitiveness without impairing said other adding As will be the art, the proportion of rial added to the emulsions will vary accordunderstood by those skilled in .ing to the nature of the latter, according to the concentration of the sensitizing material and according to creasev in' the light sensitiveness which is desired. It can be readily adjust- --ied .by trial on samples of the emulsion. When the sensitizing material is made as above descrlbed using a 10% excess of water,

which is necessary a'useful-proportion for trial is'15 parts of sensitizing solution to 1000 parts by volume larger proportions the emulsion'is although they may be otherwise satisfactory, their sensitiveness can readily be brought up to standard by mixing inmy sensitizing material, the'proportion ryarylng with amount of increase to produce a uniform product. Emulsions having almost no pracof the 0 her qualities desired in a photographic sensitive by addition tical light sensitiveness but having enough mulsion can be made usefully light ofmy material. Thus,

-im'y sensitizing material is useful in connec- L tion with 6111111810118 sitivenessand those having almost no 1n1t1a1 The increase in SGIlSltlVGHGSS .sensitiveness.

having good initial senman be: effected in one step by thoroughly stirring all of the sensitizing material into the flowableemulsion at one time; or it may be incorporated a little at a time in successive steps. gThe following example illustrates how a light sensitive photographic emulsion may be prepared and improved by the aid of my sensitizing material. Of course, my invention is 'not restricted to this illustration but is applicable in the cases of .thevery large number of widely different. emulsions in this art. The emulsion inafter' described forming operations hereare along the lines .of known {practice,-see, for instance, Die Photographie mit Bromsilber Gelatin by J.. Eder, published in Halle, Germany, in

1903b; Wilhelm Knapp as Part 111. or I Eders FAnsfuhrliches Handbuch der Phothe parts being by weig tographie. v The twojfollowingsolutions are 'made'up,

A. 900 parts of silver nitrate in 9,200 parts I of water.

the concentrated and purified sensitizing material described above.

sensitizing mate-' the amount of m',

- broken up, as byshredding,

. emulsion. For example,

melted and there 1S thoroughly mlxed 111130.

B. 690 parts of potassium bromide and 50 parts of potassium iodide in 6,100 parts of water along with 300 parts of gelatine.

- In mixing B, the halide saltsare first dissolved, the water and the gelatin-then added to the salt solution. warmed, say to 140 ample; and the silvernitrate solution gradually added to it with constant stirring. It is preferable to warm solution A before adding it to B, say tov150 F., or 160 F., for instance.

Solution 13 is'then F., or 150 F., for exiVhen solution A has been thoroughly incorporated in solution B, there are then added 43 parts of strong ammonia previously dissolved in 900 parts of water. The emulsion formed by these operations is allowed to stand fora short-time, say 15 minutes to a half hour, for example. Then, 1050 parts of gelatin are dissolved in it with thorough mixing.

until it sets to a firm jelly-" The latter is for. instance, and thoroughly washed to remove soluble salts,'such as potassium nitrate and any excess potassiumhalides. The water is,,.of course, coolenough not to melt the pieces of emulsionjelly. ,The washed emulsion is next remelted toy100 F., and 1050 parts of water soaked gelatin are thoroughly mixed into it, the temperature then being raised,

say between120 E, and 150,F., for in-' stance, forashort; time, say a few minutes.

It is then. cooled and set. It is of thelammonia or alkaline type of emulsion.

y-My sensitizing material may be usefully incorporated at any stage of the above described process of,.-prepa'ring the emulsion, even being pre-miredwith solutionsv A or' B or 'with the ammonia or with the gelatin at the initial stagesh It is convenient to add it to the otherwise complete melted emulsion pr or to coating on supports at the final stage in the process of preparing the the emulsion is reit 15 parts by volume of my sensitizing material (say theaqueous'preparation formed as above describedby using10% excess of water over that ab orbed by the, gelatine) for each 1000 parts by Volume of emulsion. Since the actual sensitizing. bodies are only a smallpart of the colloidized solids in such preparation and since such solids total. as only .a small proportion ofsaid liquid preparation bodies are very useful when addeil much less-than one part per thousand of emulsion by weight, in fact often less than one part'in that the additionof this preparation does no substantiallv dilute the emulsion, being of the order of' twoper 'centor less.

" With its light; sensitiveness increased by The emulsion is nextcooled, such as byfkeeping in a cool place,

it follows that the actual tens tizingin even-- ten thousand. It 3 will-:be noted my material,-the emulsion, being melted to the desired flowability, is coated on its support, such as glass, film, paper, etc.,in the well known way. It isconvenient to control and check the process by coating samples of the emulsion before and after the addition of my sensitizing material, the coated specimens being tried out photographically by any well known sensitometric test, or even by comparative camera exposures on the same subject. Of course, the

usual precautions are observed during the,

emulsion making and coating process, such as the use of non-actinic or safe light, cleanness of vessels and air, etc.

The different gelatins sold for photographic emulsion making may be used in the example given above, hard ones being very useful. The temperatures given are, of course, adjusted if the particular gelatin employed has physical properties, such as melt ing and setting points, which deviate considerably from the usual ones, such adjust ment being a matter of routine control.

Instead, however, of using gelatins which give emulsions of useful but lower sensitiveness even before the addition or my sensitiz ing material, an almost inert ge atin may be employedone which forms an emulsion which produces a developable image only after impractically long exposures, and then does not yield an image of desirabledensity, A gelatin which forms such a nearly inert 'emulsion may be prepared in the way de-.

scribed under the heading Preparation of ash-tree gelatin, on pages 1858 and 1859 of the Journal-of the American Chemical Society, September, 1922, Volume XLIV. No. 9, being'part ofan article by Sheppard, Sweet, and Benedict on Elasticit of purltied gelatin jellies as a function of iydrogenion concentration.- Emulsions-of impractically low light sensitiveness made by the above described process from such prepared gelatin, are transformed by my sensitizing material into emulsions which give developable images of excellent density after usefully brief exposures. I have, for example, been able to increase the light sensitiveness of such low-sensitive. emulsions over. twenty times, the exposures for a given subject being cut to less than one twentieth of the original one and the image density being made excellent by a corresponding gain. Increases of the same general order of magnitude are ma 'le'when my sensitizing material is added in similar proportions to emulsions which are'made from normal photographic gelatins or mixtures of such normal gelatins with said almost inert gelatin, and-already haveuseful but lower initial sensitiveness Different )ercentages of sensitizer produce correspondingly di'li'erent increases. The increases in'developing-out emulsions appear upon the usual developing operations. Customary pyro or metoLhydrochinon alkaline developers are as good as any for example.

For testing the power ofsensitizing material, and almost inert emulsion made, as above described, from said prepared gelatine isalso very useful. Fifteen parts by Volume of the sensitizing liquid can be added to 1000 parts of such emulsion and the.

mixture coated and tested photographically in comparison witli'a parallel sample of the unsensitized emulsion. While the addition of sensitizing material as a liquid is most convenient, the residue obtained from evaporating oil the water from said liquid can be added directly to the emulsion. In addition to having increased sensitiveness, emulsions containing my sensitizing material have improved stability or keeping qualities because of the purification of said material.

My sensitizing material maybe incorpo rated 'mto gelatin with which photographic made from the mixture have increased light sensitiveness. as compared with those made from corresponding unstrengthened gelatin.

The proportion of sensitizing material is,

of course, adjusted to give the desired control of the sensitiveness of emulsions made vfrom the gelatin, the total sensitizing inaterial. in the strengthened gelatin being thus brought above normal. It is especially effective when used in making emulsions having, at least slight alkalinity.

I My sensitizing material acts as a so-called "chemieaP sensitizer instead of an optical sensitizer. In other words, it increases the general sensitiveness of developingout photographic emulsions in which it is incorporatedythat is, to-light of substantially the same wave lengths as those to which the emulsion is sensitive before my material is added; instead of merely increasing sensitiveness to light of wave lengths the same or nearly the same as those absorbed by it. It has erties, unlike dyes. The general sensitiveness is increased; that is, throughout the normal spectral range of the emulsion instead of at only those points corresponding to the strong spectral absorption of'dye sensitizing material. My inaterial is effective in increasing the general sensitiveness of orthochromatic, panchromatic, .X-ray, and all special emulsions, as well as the ordinary or non-color-se'nsitized ones. It is preferpractically no coloring. 'propably added separatelyorindependently ot' the sensitizing dye generally, but not neces- Sarily before any dye. It is especially effective in emulsions of the ammonia or alkaline type. b

In the example given above the steps of treating with ammonia and'warming of the emulsion just before its final setting im-. prove the photographic. properties of the emulsion, especially when thelatter is made fromhard gelatins. While one or both of 1 them may. be omitted Lpreter to use both,-

' ployecl. The

in other words, my sensitizing material can act by itself' to increasethe light sensitiveness; but ripening steps are preferably emetiect of either or both of such s to help increase the light sensitivesteps,

. ness ofithe emulsions and thus give a stronger lnltla-l sensitized condition which is mul 'pensed with;

trated when it-gives a useful eiiect without have the' wide st practical use,

VVhile I have ployed, such as curring harmfully diluting the emulsion. It does not act asa photographic developer.

. I have described gelatin emulsions because at the present time they are the ones which especially the developing-out -ones. Moreover, they form the best medium for testing my sensitizing materials, the characteristic action of such materials on such emulsions being one of the best identifying criteria of such sensitizing materials. -tures of. them with each other or with gelatin, Where their nature admits such mix- Other organic colloids and 1111K tures, maybe used in making light sens tive emulsions which can be improved by adding my sensitizing material. Albumens, agaragar, gums, such as gum arabic, cellulpsic derivatives such as collodion, are instanbed.

disclosed the use of my se'nsitizer in connection .with such sensitive substances as silver bromide and silver iodide. other light sensitive substances can be em- K silveri chloride, alone or mixed with one or more of the others.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: I V

' 1. A substantially colorless organic hotographic sensitizing material derived .rom animal tissues, said material having the property of increasing-the light sensitiveness of photographic gelatino-silver-halide emulsions and being in a eoncentrated' 'torm substantially free from said tissues and from :bulky products thereof.

A biochemical sensitizing material ocin natureyvith gelatin and having the property of increasing the light sensitiveness of photographic gelatino-silverhalide emulsions of the alkaline type and being in concentrated form substantially free iromits associated gelatin.

3. A biochemical sensitizing material derived from animal sources which acts to increase the general light sensitiveness of gelatinQsiIVer-halide emulsions of the alkaline type, when it is incorporated therein, without acting to alter the grain size characteristics thereof, said material being in concentrated form substantially free from its normally associated bulgy unhy'drolyzed diluents.

4. A concentrated, purified, substantially colorless biochemical sensitizing material, which is capable, even in, the absence of dyes, of increasing the light sensitiveness of gelatino-silver-halide emulsions without interfering with the grain characteristics thereof, said material being substantially free from normally associated unhydrolyzedgelatin. v

5. A sensitizing material from biochemical sources carried in a liquid which is harmless when mixed in light sensitive emulsions, said material having the property of increasing the light sensitiveness of gelatinosilver-halide emulsions, in which it is incorporated, evenin the absence of dye and inorganic sensitizers, said materialhaving, per unit volume, greater sensitizing power than said sources.

6. A biochemical material derived from the same sources as photographic gelatin and possessing the light sensitizing principle of photographic gelatin in concentrated form substantially free from the bulk of its normally associated gelatin. H

7. A light sensitive emulsion comprising a colloid, particles of photographic sensitive salts suspended therein, and an independent organic sensitizing material difierent from said colloid upon which at leastpart of the general lightsensitiveness of the emulsion depends.

8. A photo no-silver-hali e light sensitiveness comprising a mixture 0 aphic developing-out gelatiemulsion of relatively high the constituents of a gelatino-silver-halideemulsion of lower light sensitiveness and an independent biochemical sensitizing material upon which depends the difierence between said lower and said high light sensitlvfieSS.

.9, A photographic gelatino -silver halideemulsion of the alkaline type comprising a mixture of gelatin, silver halide particles, and a biochemical sensitizing material, sub-. stantially free from itsnormally associated bulky impurities, which increases the light sensitiveness of said emulsion.

10. A photographic gelatino-silvershalide emuls on comprising a suspension in-gelatin of silver halide particles, and an independent biochemical sensitizing extract upon which at least part of the light sensitiveness of said emulsion depends, the volume of said extract being less than the order of 2 per cent of the total volume of the emulsion.

11. A. photographic gelatino-silver halide emulsion of relatively high light sensitiveness substantially free from dye sensitizers, comprisinga mixture of the constituents of a gelatino-silver-halide emulsion, havin determined grain size characteristics and lower light sensitiveness, and independent biochemical sensitizing material upon which depends the difierence between said lower and said high light sensitiveness While said grain size characteristics remain substantially constant.

12. A photographic gelatino-silver-halide emulsion of the alkaline type comprising a suspension in gelatin of silver halide part cles and an independent biochemical sens tizing material, the percentage of light sensitiveness due tosaid material. being greater than the percentage of the total volume taken up by said material. 13. A photographic gelatino-silver-hahde emulsion comprising a suspension in gelatin of silverhalide particles and an independent biochemical sensitizing material, the prpportion of the light sensitiveness of said emulsion due to said material being of the order of magnitude of 95 per cent, While the volume of the material is of the order of magnitude of 2 per cent of the volume of the emulsion.

14. A photographic gelatino-silver-halide emulsion comprising the constituents of a gelatino-silver-halide emulsion of a lower light sensitiveness of the order of one-twentieth of the light sensitiveness of the first named emulsion and an independent biochemical sensitizing extract upon which the greater light sensitiveness of the first named emulsion depends, said sensitizing extract being substantially free from effect upon the non-photographic qualities of said emulsions.

15.. A photographic gelatino-silver-halide emulsion substantially free from sensitizing dye comprising a mixture of gelatin, silver halide particles, and an independent organic sensitizing material upon which at least part of thelight-sensitiveness of said emulsion depends, said material being substantially free from effect upon the non-photographic qualities of said emulsion.

16. A. photographic gelatino-silver-halide emulsion comprising gelatin, silver halide particles suspended therein, and an independent biochemical sensitizing extract upon which at least part of the light sensitiveness of said emulsion depends, the physical properties of said emulsion which correspond to the physical properties of said gelatin being substantially unaltered by said sensitizing extract.

17. A photographic gelatino-silver-halidc emulsion having characteristics of manufacturing standard comprising the constituents of a gelatino-silver-halide emulsion of substandard light sensitiveness but otherwise of standard characteristics and an independent concentrated biochemical sensitizing material upon which the difierence between said substandard and standard light sensitiveness depends, the other characteristics being substantially independent of said sensitizing material.

18. A photographic gelatino-silvenhalidc emulsion comprising a mixture of gelatin, silver halide particles, and an organic sensitizing material upon which at least part of the light sensitiveness of said emulsion depends irrespective of dye sensitizers, said material being substantially free from bulky colloids.

19. A photographic gelatino-silver-halide emulsion having light sensitiveness over a definite spectral range and having definite grain size characteristics, said emulsion comprising the constituents of a gelatino-silverhalide emulsion having substantially the same definite grain size characteristics but having a relatively lower light sensitiveness over said spectral range and a sensitizing material upon which depends the difference in light sensitiveness between the first named emulsion and said second named emulsion over said spectral range, the grain size characteristics being substantially independent'of said sensitizing material.

20. A photographic colloid-si-lver-halide emulsion comprising a colloid, silver-halide particles suspended therein and a biochemical sensitizing material different from said colloid upon which the general light sensitiveness of said emulsion depends, the ratio of said material to said silver halide being substantially independent of the ratio of said colloid to said silver-halide.

21. A pl'iotographic gelatino-silver-halide emulsion comprising gelatin, silver halide particles suspended therein and a sensitizing material upon which a large part of the light sensitiveness of said emulsion depends independently of dyes, the ratio of gelatin to silver-halide being substantially unaffected by said material.

22. In the process of preparing a photographic emulsion, incorporating therein a sensitizing material derived from animal tissues but in concentrated form substantially free from said tissues and from bulky products thereof, said material increasing the light sensitiveness of said emulsion.

23. In the graphic gelatino sensitivesilver salt emulsion. of the alkaline type, incorporating therein a biochemical sensitizing material in process of preparing a photoconcentrated form substantially free from gelatin to increase thelight sensitiveness of said emulsion.

2%. In the process of preparing .a photographic colloid-sensitive-silver-salt emulsion,

graphic biochemical colloid-sensitive-silversalt emulsion, incorporating therein a sensi tizing extract different from said colloid and obtained from biochemical sources, the said extract, per unit volume, being greater than that of said sources, to increase the light sensitiveness of said emulsion.

26. In the process of preparing a photographic colloid-sensitive-silver-salt emulsion, incorporating therein independently of any dye sensitizers an organic sensitizing material in concentrated form substantially free from bulky dilueuts, said material increas-,

ing the general light sensitiveness of said emulsion.

27. In theprocess of preparing a photograplnc colloid-sensitive-silver-salt emulsion, incorporating therein separatelyfrom dyes 'a biochemica-l sensitizing material in concentrated form substantially free from nonvolatile diluents, said material increasing the general light sensitiveness of said emulsion Without acting to increase the size of the grain thereof.

28. In'the process of preparing a photographic developing-out gelatino silver-halide' emulsion of the alkaline type incorporating therein an organic sensitizing finaterial in con-.entrated form substantially free from unliydrolyzed gelatin, said material increasing the generallight sensitiveness of said emulsion.

29. In the process of preparing a photographic gelatino-silver-halide emulsion incorporating therein a sensitizing material from biochemical sources, having greater sensitizing power, per unit volume, than that of said sources, said material increasing the light sensitiveness of said emulsion without increasing the grain size thereof.

30. In the process of preparing a photographic gelatino-silver-halide emulsion of the alkaline type, incorporating therein sensitizing material which occurs in dilute form in organic sources and is contentrated to; be more active, volume for volume, than :said source, said material increasing the general light seflsitiveness of said emulsion.

' 31. Intlie process of preparing a photographic gelatino-silver-l alide emulsion, incorporating therein separate from any sensithan one thousandth the said material 4 gelatin, said material increasing the;

general light sensitiveness of said emulsion without acting to increase. the grain size thereof.

33. In the process of preparing photographic gel atino-silver-halide emulsion, the steps of taking up a concentrated organic sensitizing material, independent of dye and inorganic sensitizers, in a liquid vehicle which can pass without harm into such emulsion, and incorporating the liquid carrying the material into the emulsion.

34. In the process of preparing a photographic gel-atino-silvcr-halide emulsion, in-.

corporating therein aconcentrated organic sensitizing-Amaterial, substantially free from bulky diluents, which increases the light sensitiveness of said emulsion irrespective of dyes and inorganic sensitizers.

35. In the process of preparing a photographic gelatiiio-silver-halide emulsion, incorporating therein a sensitizin extract from biochemical sources and aving a higher sensitizing power per unit volume than said sources, said material increasing the light sensitiveness of said emulsion in addition to etiects of dyes and inorganic sensitizers.

36. In the process of preparing photographic colloid-sensitive-silver-salt emulsions, incorporating therein an organic sen sitizing material which greatly increases the general light sensitiveness of said emulsion even in the absence of dyes without substantiallydiluting the emulsion, theactivesensitizing bodies in said material being less weight of said. emulsion.

37. In the process of preparing photographic gelat-inmsilver-halide emulsions of the alkaline type, incorporating thereinorganic-sensitizing material which causes an increase in the light sensitiveness of said emulsion, the active bodies in said material being less than one thousandth the Weight of said emulsion.

38. "In the processof -manu-facturing a. photographic emulsion, extracting from a biochemical source a non-dyeing sensitizing material in a form substantially free from. bulky associateddilue-nts, and incorporating sufficient of said material .and a different biochemical colloid in preparing saidemul-. sion to increase the light sensitive-ness ot the latter. i

' Q44. In the.

39; In the process of manufacturing a' photographic biochemical colloid-sensitivesilver-salt emulsion, extracting fromorganic tissues a sensitizing material different from said colioid and in concentrated form substantialy free from" said tissues and bulky derivatives thereof, and incorporating sufficient of said material in preparing said emulsion to increase the light sensitiveness of the latter. 1

' 40. In the process of manufacturing a photographic gelatino-silver-halide emulsion, extracting from a gelatin source a sensitizing material in concentrated form and adding said material to said emulsion.v

41. In. the process of manufacturing a photographic biochemical colloid-sensitivesilver salt emulsion, extractingfrom a biochemical source a sensitizing material different from said colloid in which the concentration of active sensitizing bodies is greater than in said source and incorporating suflicient of said material in preparing said emulsion .to increase the light sensitiveness of the latter,

42. In the process of manufacturing a photographic gelatino silver halide emulsion, extracting from .a biochemical source a sensitizing material in concentrated form, and incorporating-in preparing saidemulsion sufficient of said material to increase its light sensitivenss, said sensitizing material being free from effect on the grain sizecharacteristics of said emulsion. L

43. In the process of manufacturing a photographic gelatino-silver-halide emulsion, extracting from a biochemical source a sensitizing material in concentrated form and incorporating in preparing said emulsion sufiicient of said material to increase its light sensitiveness' irrespective ofthe action of dyes and inorganic sensitizers. I

process of manufacturing a photographic gelatino-silver-halide emulsion, extracting from a biochemical source a concentrated sensitizing material and incor oratin said material in said emulsion .corporating approximately 2 chemical non-dyeing to increase the light scnsitiveness thereof,

thefproportion by volume of'said material v Leing of the order ofmagnitudc of two per cent.

45. In the process of manufacturing a photographic gelatino-sllver-halide emulsion, extracting from a biochemical source aconcentrated sensitizing material and inper cent by volume of said material in said emulsion, the material increasing the light 'scnsitiveness' of said emulsion approximately 20 times.

L6, In the process of manufacturing a photographic emulsion, extracting a, biosensitizing material away fron'iat least part of its associated bulky impurities, by treatment with a fluidvehicle, and incorporating sufficient of the extract and a different biochemical colloid in preparing said emulsion to increase the light sensitivencss thereof 47.'In the process of manufacturing a photographic biochemical colloid-sensitivesilver-salt emulsion, treating an animal source containing sensitizing materialassociated with bulky 'diluents with a fluid into which said IllfitllfihSPI'GitdS more rapidl than said impurities until said material 1s concentrated in said fluid and freed from at least part of said diluents, and incorporating suiiicient of the purified extract thus obtained in said emulsion to increase the light sensitiveness thereof.

48. In the process of manufacturing photographic gelatino-silver-halidc emulsion, treating a. biochemical source containing a sensitizing material and bulky colloid diluents with a fluid into which said material spreads more rapidly than said diluents until an extract of material in'said fiuid'is obtained separating at least part of said fluid from said extractvand incorporating sufficient of said extractin said emulsion to increase the light sensitireness thereof.v

49. In the process of .manufacturing a photographic gelatino-silver-halide emulsion, extracting with water from a-gelatin source asensitlzing material, and adding suiiicient of said aqueous extract to said,

emulsion to increase the thereof;

5O. In the process of manufacturing a photographic biochemical colloid-sensitivesalt emulsion of higher sensitiveness the steps of forming a biochemical colloid-sensitive-salt emulsion of relatively lower light sensitiveness, extracting from an animal source a sensitizing material, and incorporating s'uflicient of said matcrial in said emullight sensitivcnas sion of lower light sensitiveness, to changeemulsionof lower light sensitiveness sufli cient of said material to change it nto said emulsion of higher light sensitiveness, said grain size characteristics remaining substan-v tially constantQ p 52. In. the process of manufacturing a photographic biochemical colloid-sensitivesilver-salt emulsion of relatively higher light i sensitiveness, forming a biochemical colloidsensitive silver-salt emulsion of lower lightsensltiveness and having a definite ratio of extracting a biochemical sencolloid to salt, sitizlng' material from a biochemical source,

and adding suflicient of said sensitizing material to said emulsion of lower light sensitiveness to change it to said emulsion of higher light sensitiveness without substantially altering said ratio.

53. An intermediate free from silver salts and halid salts for use in making photographic emulsions comprising an emulsionforming colloid and an independent biochemical sensitizing material difi'erent therefrom and incorporated therein, said material being substantially free from its normally associated bulky diluents, said intermediate havingthe property of forming emulsions of higher light sensitiveness than those formed under parallel conditions from said colloid without the material.

54. An intermediate for use in making photographic emulsions comprising a biochemical emulsion-forming {colloid and an independent biochemical sensitizing material difierent from said colloid incorporated therein, said material being derived from a biochemical source but containing a higher concentration of active sensitizing bodies.

than said source, sald intermediate having the property of forming emulsions of'higher light-sensitiveness than those formed under parallelconditions from said colloid without the material. v V p r 55. An intermediate for forming photographic gelatino-silver-halide emulsions comprising a mixture of gelatin and an independent sensitizing material from a gelatin source, said material being substantially free from its normally associated gelatin, and said intermediate having the property of forming gelatino-silver-halide emulsions of greater general light sensitiveness than those formed under parallel conditions from said first named gelatin without said material. a

56. An intermediate for forming photoemulsions, comprlsing a mixture of gelatin and an :independent biochemical sensitizing material in concentrated form said intermediate having the property of forming gelatino-silverhalide emulsions of higher light-sensitiveness but substantially the same grain size characteristics as those formed under parallel conditions from said gelatin without said material; 1

57. An intermediate for use'in making photographic emulsions comprising an emulsion-forming colloid and an independent sensitizing material without dye sensitizing action, said intermediate havin the property of forming emulsions of big er light sensitiveness than those formed under parallel conditions from said colloid without said material.

58. An intermediate for forming hotographic gelatino-silver-halide emu sions, comprising a mixture of gelatm and an mdependent sensitizing material in concen-.

trated forin, said intermediate having the property of forming gelatino-silver-halide emulsions of, higher light sensitiveness, ir-v respective of the action of dyes and morganic sensitizers, than those formed under said tissues and from bulky products thereof and capable of increasing the light sensitiveness of said emulsions before silver salts or halid salts are incorporated therein.

60. In the process of preparing an inter-' mediate for the manufacture of photographic emulsions the step of incorporating in a biochemical emulsion-forming colloid an independent biochemical sensitizing material different from said colloid derived from a biochemical source but having a higher concentration of active sensitizing bodies than said source, and having the property of increasing the light sensitiveness ofv said emulsions. I

61. In the process of preparing an intermediate for the manufacture of photographic gelatino-silver-halide emulsions the step of incorporating in gelatin an independent sensitizin material from a gelatin source but substantially free from its normally associated gelatin and having the property of increasing the light sensitiveness of said of lncorporating in gelatin an independent concentrated biochemical sensitizing material which increases the li ht sensitiveness of said emulsions without a ecting the grain size characteristics thereof.

63. In the process of preparing an intermediate for the manufacture of gelatino-silver-halide emulsions, the step of incorporating in gelatin an independent sensitizing material which increases the light sensitiveness of said emulsions irrespective of. the action of dyes and inorganic sensitizers. .64, In the process of manufacturing an intermediate for use in making photographic emulsions, extracting from a biochemical source a sensitizing material in a form substantially free from bulky associated diluents, and incorporating said material in a photographic emulsion-forming colloid prior to the incorporation of silver salts or halid salts therein.

Signed at Rochester, New York this 4th day of June 1924:. t a

REUBEN F. PUNNETT.