US1712439A - Color photograph and method of producing same - Google Patents

Description

May 7, 1929- w. v. D. KELLEY 1,712,439

COLOR PHOTOGRAPH AND METHOD OF PRODUCING SAME Filed May 24. 1920 l -wnll mmm mmm Illu u -Patented May 7, 1929.

UNITED STATES *1,712,439 PATENT o-EFlcE.

WILLIAM v. D. KELLEY, or NEWARK, NEW JERSEY, AssIGNoE, BY MEsNE AssIGN. MENTS, 'ro MAX E. LU roN'r vITAcoLoE coEroEATIoN, or Los ANGELES. cALI. EoENIA, A coEroEA'rIoN 0E DELAWARE.

COLOR PHOTOGRAPH AND METHOD OF PRODUCING SAME.

Application filed May 24,

rllhis invention relates to color photography and has particular reference to a process and a product whereby either subtractive or additive composite pictures or transparencies can be provided for reproducing colors of nature by using the original sensitiveness of a single colloid emulsion carrier.

Although various methods have been described and patented for producing subtractive. color pictures using two or more difierent color value images on the same side of the transparent support, ranging from resensitizing` with a new coating for each successive print, (Selle, 654,766 July 31, 1900), to using the silver of the emulsion for one rint, and the gelatin for a second print (Cox, r. 15,648 lune 30, 1914), or resensitizing the gelatin with iron salt (Ives, 1,278,668 September 10, 1018), so far as l am aware, no commercially workable process using such methods has yet been evolved. It has also been proposed, but not comniercially Worked, (Fox 1,166,123, December Q8. 1915) to print an image in part of the emulsion, develop and tone said ima-ge, print the second image in the residue of sensitive silver if any, develop and bleach with cle-coloring of the first image by development ot' the second, and then dye the second image and restore the color of the first image. This process is unsatisfactory because it discloses no way of preventing redevelopment of silver in the first image during development of the second image, due to the presence of developable silver compounds such as silver ferrocyanid.v causing the final image' to be unsatisfactory in detail. This process is also uncertain in result by reason of the difficulty of retaining sufficient sensitiveness for the sec ond print, while the restoration of the decolored first image is not always accurate in color rendering, so that it may have to be modified later by further toning or dyeing treatment, or else the other image has to be modified in color to balance. Furthermore, the bleaching baths employed for dyeing images resulting from exposure of light sensitive silver salts in the above processes are only adapted for basic dyes, which are diflicult to work with commercially because they are diehroic, giving different colors with different densities. The processes depending upon resensitizing and dyeing the gelatin, as by potassium bichromate or by iron salts, are

1920. Serial No. 383,848.

objectionable because of slowness and increased manipulations required. It has further been proposed to combine a red copper toned image with basic dyes to improve the red obtainable from copper or basic d es alone (Ives 1,300,616, April 15, 1919), gut th1s .does not overcome the limitations inherent 1n either alone, nor when combined with a complementary colored image produce the desired transparency and color balance in the final film.

The aforementioned patents mostly state that reglstratlon of the two images should be had, but none state how this can be accompllshed for quantity commercial output of color motion picture film, yet Without accurate registration of the two images throughout a long strip, no successful results can be accomplished.

Since a method employing single coated positive film carrying different complementary images therein has an initial advantage over methods using double coated film by reason of cost of stock, such initial advantage may readily be lost unless the subsequent stepspermit the use of' ordinary negatives, are simple and rapid to work, and sufficiently flexible to meet the variations inevitably encountered in large scale operations with subjects made under diverse conditions.

According to this invention generally, the original sensitive silver salt in the emulsion is used for both images, a good second print being assured by temporarily slowing the original emulsion with a fugitive dye which washes out in the first development, leaving an ample residue of sensitive emulsion for the second print. The first ima e printed, for example, through the back of t e support without being fixed, is bleached to be dye absorbent, in a bleach having the peculiar characteristic of not producing light sensitive silver salts or silver salts which are affected, as by being reduced to black silver, by the developing of the second image. After printing the second image from the front and developing, both images are fixed in sodium thiosulphate, and the first, being still recep* tive to acid or azo dyes, can be colored as redorange and the second toned blue green, as with ferrie ammonium citrate and potassium ferricyanid, or bleached and dyed blue green. This will produce a subtractive two, color transparency on the'principle of I ny Patent 1,259,411 March 12, 1918, but 1n a single coating, the images being registered by the means and method hereafter disclosed.

For an additive transparency on the principle disclosed in my Patent 1,337,775, April 20, 1920, the design screen prints shown in Figure 1 of said patent will be separately made, one from the back and one from the front, before or immediately after, the prints from the negatives, so that each' design and i'ts intervening image sections will color alike in complementary colors. Registration of the design printing screens is by the pin `means shown in Figure 7 hereof. A modification of this principle is in the use of line designs, one crossing the other` which avoids the necessity of exact registration of the lines of one desi with the spaces ofthe other, it being found that the black spots at the line crossings neither objectionably showin projection, nor reduce the illumination, nor degrade the colors.

In the accompanying drawings,

Fi ure 1 is an elevation of the novel positive lm to be colored,

Figure 2 is an elevation after the first image is printed and developed,

Fi ure 3 is the same with the first image bleaclied, and the second developed,

Figure 4 is an elevation showing the first image dyed one color, as red, and the second toned, as blue-green,

Figure 5 is an elevationsimilar to Figure 2, of an additive transparency, y

Figure 6 is an elevation similar to Figure 3 of the same with the first image and design bleached, and the second image and registering design ready to be toned,

Figure 7 is a modification, with line designs crossing each other,

Figure 8 is an elevation of Figure 7,

Figure 9 is an elevation showine the crossing lines on oppolitely coated Stoch,

Figure 10 shows a conventional red value negative,

Figure ne ative,

' igure 12 shows the finished positive of Figures 7 and 9, and

Figure 13 represents an elevation of a sensitive screen carrier such as a negative embodyin the invention.

y this invention a single emulsion carrying light sensitive material, such as silver bromid, is to be subjected to two exposures, with an intermediate treating step after the first exposure of such character that no redevelopment occurs because of the second development.

The two exposures can be in the respective opposite portions of the emulsion, one being 11 a complementary green value made through the back of a transparent carrier, and one on the face of the emulsion. An additive two color transparency on the prinmaking the second print.

ciple of my Patent 1,337,775 of April 20, 1920, can also be made in one emulsion by printing from opposite sides. The two exposures can be side by side to embody the same additive principle, as in case a finely divided additive screen is to be provided for making a single negative of two or more colors. In all of these alternatives success is obtained by so controlling the process as to prevent redevelopment of the first image by development of the second image, after the first has been treated. By solving this diflieulty, it is possible to produce transparencies from single coated emulsion at a considerable saving in cost of material and labor over previous processes using double coated positive, or recenting processes.

In making a subtractive transparency, I start With a single coated positive plate or film, differing only from ordinary positive plate or film in being provided with a fugitive or soluble light retardinfr dye, such as a yellow mono-azo salt of sodium which slows the passage of light through the emulsion to such extent as to leave a substantial residue of sensitiveness in the opposite iortion from where the light enters, sufficient 0r the second print. This dye Washes out during the first development, and it is immaterial whether the first print be made in the face of the emulsion or through the back, but I prefermakin g the first print through the transparent back. The second print can be made through the face of the emulsion in which the first print has been made, because of the first print being transparent when bleached.

The next step is to Wash to remove the fugitive dye and any residue of developer. The next step is to harden the gelatin as by immersion for ten minutes in 10% formalin solution, and then bleach in a solution having the peculiar characteristic of preventing redevelopment of silver salts in the first image during the second developing.

A satisfactory bleaching bath is:

Water 100() ce.

Sodium bichromate 2. 235 g. Ammonium chrome alum 2. 302 g. Cupric sulphate 12.480 Sulphuric acid .083 g.` Potassium bromid 17. 835 g.

but other baths can be used or the proportions may be varied. Apparently a copper chromium mordanting .salt is formed in situ with the transparent silver salts formed from the developed black silver. which mordant ing salt will fix acid or azo dyes without being affected by the fixing bath, or by certain tening baths, or by gelatin dye baths, or by the second development.

The first image is now transparent and barely visible in refiected light, and there is a residue of sensitive silver salt snflieient for In quantity pro- Fili duction, the period of exposure for the second print can be shortened by reviving the tilm speed by a five minute bath in tlhroinic acid 6. 25 g. Fotassium broniid 12. g. ll/later 1000 cc.

'lhe iilm is then washed and dried and is now ready' to receive the second print, which is made in registry with the first print and then developed with a developer such as pyro, which will not afi'ect the first bleached print, it being observed that the rst print has not yet been xed out in sodium thiosulphate according to usual practice. After the second print, made in the washed and dried revived emulsion is developed, the entire film is fixed in sodium thiosulphate, washed and-preferably dried, bein now in the condition shown in Figure 3, having the bleached image in one stratum and the developed black image in the other, or in different portions of the same stratum.

The film is now dyed in a mixture of red and orange acid or azo dyes, to give the desired red value, dyes such as alkali salts of tetrabioniodichlorotluorescine, being suitable for dyeing red, it being understood that the bleached image which is te be dyed is of a record complementary to the d ve color, being in this case printed from a green blue negative. lt the bleached image is to be dyed green or green blue it will be printed from a red value negative and a suitable dye will be calcium, magnesium or sodium salt of the disulplionic acid of m-oxy-tetia-alkyldiamidotriphenyl-carbinol.

'llhe second print, it made from a red value negative can readily be toned blue green, as by the cyanotype process, wherein ferrie terrocyanid gives a satisfactory bluegre-en color and transparency. If the tone coloi is to be red, as where the bleached image was dyed blue green, various red toning baths are .known such as uranium, copper, etc., not

necessary to be described in detail here, being described in Cassells Cyclopedia of Photography, and other standard works. A final washing after the toning completes the film. After the dyeing step ordinary washing should clear the dye from the whites, but in some instances the wash water can be slightly acidulated with acetic acid.

ln Figures 1 to 4 inclusive, 1 represents the transparent base, 2 the emulsion, 3 the first image to be bleached and dyed and 4 the second image to be toned.

ln Figures 5 and G, a design will be printed in each stratum of the positive with the image, and colored a like color as in my Patent 1,337,775 April' 20, 1920, the designs displaced so that a clear portion of one overlies the design portion of the other. Lines, squares and other geometric patterns can be employed, as long as' the clear portions are about equal to the design portions. ln Figure 5 the lines are represented by 5 and the spaces by 6 in the inner surface and in Figure 46 the spaces are represented by 7 and the lines or other designs by 8.

I n order to avoid the difficulty of registering the spaces of one design print with the designportions ofthe other, the arrangement'shown in Figure 7 can be used, wherein a design made up of parallel lines and spaces can be used for one print and the same design with the lines and spaces transverse thereto for the other. In such cases the crossings of the lilies will produce blacks, which have no effect iii the additive production of color, the clear spaces will show white where White is to appear or black for black, or red or green, as the case may be, while the portions of the line designs between the crossings will in white portions of the picture show respectively red and blue green and in other portions of the picture according to the color to be rendered, these small portions of red and blue green, additively giving white. In Figure 8 an elevation of Figure 7 is shown, the designs crossing at 900, 9 being the inner design and 10 the outer design, while in Figure 9 a double coated transparent stock 1 has these respective designs 9 and 10 on opposite sides. Figure 10 shows a conventional red screen negative and Figure 11 a conventional green screen negative, while Figure 12 shows, subject to limitations ot drafting, the resultant transparency formed by superposing prints from the negatives of Figures 10 and 11. In Figure 12 the section lV shows white by the additive effect of the white section 11, red sections 12 and green sections 13, the black sections 14 formed by the crossings being ineii'ective. The red section R will be composed of the parallel red bands constituting continuance of the sections 12 separated by black bands 15. The black section B will be all black owing to the combined subtractive eii'ect of colored lines and images. The green` section G will be produced bythe green bands constituting continuance ofthe section 13 separated by black bands 16 similar to the bands 15, but transverse thereto.

In Figure 13 the base 1 is provided with an emulsion 17 on one side and on the opposite side or the same side is another portion which will be printed with a screen design having image portions 18 to be bleached and dyed red and interventing portions 19 to be toned green to constitute a color screen through which the emulsion 17 can be exposed to ohtain an additive color value record. Ordinary stock can be first provided with the screen, and then sensitized for exposure, either on the same side or on the opposite side, or the screen portion can be made-and colored before the image portion. This furnishes a simpler method of obtaining a screen plate or film than has heretofore been proposed, since, so far as I am aware, previous efforts along these lines have not been successful owing to the difficulty of obtaining two colors side by side in the same stratum from separate prints without causing the first image to be redevelopcd durlng printing of the second. This difficulty is overcome b y the procedure herein described, so that this invention is not to be restricted to a process of producing plural images in different strata of the same sensitive emulsion, as it is equally applicable for producing different images, side by side, in either instance one to be colcred by dyeing or dye-toning and the other T most conveniently by chemical toning.

In the several possible variations of this invention, it will be seen that an important feature is the employment of such a bleach as Will not produce, before final fixing out, silver compounds redevelopable by the second developing, an example of such compounds being silver ferrocyanid or other compounds, more or less sensitive to light and formed by various previously known bleaches, such as that given in Capstaff 1,273,457, July 23, 1918, or which redevelop in the .second developer, Whether or not light sensitive.

An important feature resides in the printing of the two images in registry, which is accomplished as herein shown by employing the ordinary standard elongated film perforations for registration. A preferred method is to select one perforation in the negative and to pass through this perforation K a full-fitting pin 20, and if, desired through an opposite perforation a cooperating pin 21 fitting the two perforations from top to bottom, but not from side to side, so that all the relative shrinkage of the negative to the positive is taken up on one side at the fullfitting pin 20. The redevelopment and drying of the positive after the first print and before the second causes a slight shrinkage, but by making the second print using a corresponding perforation of the negative and the same positive hole and full-fitting pin for registration, the second image comes in practically identical relation with the first, and no difficulty arises due to shrinkage. lVliether printing on the same side of the positive or on opposite sides, the same positive hole 1s used in each case for the full-fitting registration pin 20, and where the second pin 21 is used the same positive hole is used in both cases for that pin.

The invention is applicable to all kinds of Work other than motion pictures, including plates and paper With suitable modifications and also to stereoscopic Work.

Where the claims specify acid dyes, I intend to cover azo d ves as well without expressly so stating in the alternative form. By coloring is meant broadly either coloring with a solution of a soluble dye stuff, sometimes called dye-toning or dyeing as herein; or

y coloring with an insoluble lake lor precipitate of a salt or salts of a metal, sometimes called chemical toning, or toning as herein.

The bleaching and dyeing process herein disclosed, and the products thereof, are claimed in my copeiidin application, filed April 25, 1918, Serial o. 230,676, and issued April 4, 1922, and this application is in part a continuation thereof.

What I claim is:

1. Process for differently coloring separate images in a colloid carrier, consisting in forming therein a bleached dye absorbent image and a separate reduced silver image, dyeing the former and coloring the latter to provide different colors.

2. Process for differently coloring separate images in a colloid carrier, consisting in hardening the carrier, forming therein a bleached dye absorbent image and a separate lreduced silver image, dyeing the former, and coloring the latter to provide different colors.

3. Process for differently coloring separate images in a colloid carrier, consisting in forming in a portion thereof a bleached dye absorbent image containing a silver compound non-redevelopable by subsequent developing, printing and developing a second silver image in another portion thereof, fixing, dyeing the bleached image to one color, and transforming the silver image to a second color.

4. Process for differently coloring separate images in a colloid carrier, consisting in forming therein a bleached image absorbent to acid dyes and a separate reduced silver image, and then dyeing the former with an acid dye and toning the latter to provide different colors.

5. rocess for differently coloring separate images in a colloid carrier, consisting in hardening the carrier, forming therein a bleached image absorbent to acid dyes and a separate reduced silver image, and then dveing the former with an acid dye and toning the latter to provide different'colors.

6. Process for treating a developed innige of reduced silver in a carrier containing in addition, a residue of light sensitive silver salt, consisting in bleaching the reduced silver to be absorbent to acid dyes while rendering the silver salt of the bleached image nonredevelopable by further developing, printing a second image in said residue, developing the second image, and fixing both images.

7. Process for treating a Ydeveloped Vimage of reduced silver in an emulsion containing light sensitive silver salt, consisting in hardening the emulsion, bleaching the reduced silver to be absorbent to acid dyes while ieiidering the resulting silver salt of the image non-redevelopable by further develo wing, ieviving the speed, printing and developing a second image in the light sensitive silver salt, and fixing both images.

tid

8. Process of producing a composite photographic picture suitable for coloring with a plurality of colors, which consists in printing an innige in one portion of sensitive emulsion, developing, treating saine in such manner as to prevent redevelopment by subsequent developing, printing and developing a second image iii the other portion of said emulsion, and fixing, whereby to provide two images, the first capable of being dyed and the second capable of being toned, each independently of the other.

9. Process of producing a composite color transparency which consists in printing an image in one portion of sensitive emulsion, developing, treating same in such manner as to prevent redevelopment in subsequent developing, printing and developing a second image in the portion unaffected by the said treatments, fixing, and independently coloring said images each a different color Without affecting the other.

10. Process of producing a two color transparency composed of a toned image in one color and a dyed image in another color, in a single emulsion, consisting in printing and treating the firstimage so as not to redevelop during developing of the second, then printing and developing the second image, fixing both images, and independently dyeing the first image and toning the second to produce respectively different colors in said images.

l1. Process of producing a two color transparency in a single emulsion consisting in providing the sensitive emulsion with a fugitive light retarding medium, exposing one portion of such emulsion to obtain an image while said medium protects the remaining portion, developing said image, removing said medium, treating said developed image to fix a color, printing a second image in the previously protected portion of said emulsion, developing said second image, fixing both images, and independently co1- oring said images each a different color without affecting the other.

12. Process of producing a two color transparency in a single emulsion consisting in providing the sensitive coating with a fugitive light retarding medium, exposing one portion of such emulsion to obtain an image while said medium protects the remaining portion, developing said image, removing said medium, treating lsaid developed image to both fix a color and to prevent redevelopment by subsequent developing, printing alsecond image in the previous y protected portion of the emulsion, developing said second image, fixing both images, and independently coloring said images each a different color without affecting the o ther.4

13. Process of producing a two color transparency in a single emulsion consisting in making a print in one portion of the emulsion, developing, bleaching with a bath l containing copper and chromium salts, printing and developing a second image in an unexposed portion of the emulsion, fixing both images, and independently coloring said images each a different color without affecting the other.

14. Process of producing a. two color transparency in a single emulsion consisting in making a print 1n one portion of the emulsion, developing, bleaching with a bath containing copper and chromium salts, reviving the speed, printing and developing a second image in an unexposed portion of the emulsion, fixing both images, and independently coloring said images each a different color Without affecting the other.l

15. Process of producing a subtractive transparency consisting in providing a sensitive silver emulsion with a fugitive light retarding medium, printing an image in one stratum thereof, bleaching said image in such manner that the bleached silver salts will not redevelop b further developing, printing and developing a second image in another originally sensitive stratum of said emulsion, dyeing the first image to one color, and transforming the second to another color.

16. Process for producing two images in one colloid carrier from the original light sensitive salts thereof, consisting in printing an image in one portion thereof while protecting a remaining portion from the printing light, developing, treating the developed image to be dye absorbent and'non-redevelopable, printing a second image in the originally light protected portion, developing said second image, and fixing both ima es.

g1? Process for producing two images in one colloid carrier from the original light sensitive salts thereof, consisting in printing an image in one portion thereof while protecting a remainin portion from the printing light, developing, treating the developed image to be transparent, dye absorbent and non-redevelopable, rinting a second image in the originally light sensitive protected portion, developing said second image, and fixing both images.

1 8. Process for producing two images in one colloid carrier from the original light sensitive salts thereof, consisting in printing an image in one portion thereof while protecting a remaining portion from the printin' ight, developing, treating the develope image to be acid-dye absorbent and non-redevelopable, printing a second image in the originally light sensitive protected portion, developing said second image, and fixing both images.

19. Process for producing two images in one colloid carrier from the original light sensitive salts thereof, consisting in printing an image in one portion thereof while protecting a. remaining portionv from the printin light, developing, treating the develope image to be transparent, acid-dye absorbent and non-redevelopable, printing a second image in the originally light sensitive protected portion, developing said second image, and fixing both images.

20. Process for producing two images in one colloid carrier from the original light sensitive salts thereof, consisting in printing an image in one portion thereof while preventing complete penetration by the printing light, developing, treating the developed image to be dye absorbent and nonredevelopable, printing a registering second image in the originally light sensitive unpenetrated portion, developing said second image, and fixing both images.

21. Process for producing two images in one colloid carrier from the original light sensitive salts thereof, consisting in printing an image in one portion thereof while preventing complete penetration by the printing light, developing, treating the developed iniage to be transparent, dye absorbent, and nonredevelopable, printing a. registering second .image in the originally light sensitive unpenetrated portion, developing said second image, and fixing both images.

22. Process for producing two images in' one colloid car-rier from'tlie original light sensitive salts thereof, consisting in printing an image in one portion thereof while preventing complete penetration by theprinting light, developing, treating the developed image to be acid-dye absorbent, and non-redevelopable, printing a registering second image in t e originally light sensitive iinpenetrated ortion develo ino' said second ima e and fixing both ima es.

23. Process or producing two images in one colloid carrier from the original light sensitive salts thereof, consisting in printing an image in one portion thereof while preventing complete penetration by the printin light, developing, treating the develope y image'to be transparent, acid-dye absorbent,' and non-redevelopable, printino` a registering second image in the originally light sensitive unpenetrated portion, developing said second image, and fixing both images.

24. In the process of obtaining two images in a single colloid carrier from the original light sensitive salts thereof, incorporating in the carrier a fugitive light retarding medium, printing an image from one side thereof while said medium retards passage of the printing light through the carrier, developing the image, removing the medium, treating the first image to be dye absorbent and nonredevelopable, printing a second image in the unpenetrated portion of the carrier, developing and fixing both images.

25. Process of producing a subtractive two color transparency in a single emulsion on a.

bleaching same, printing a second image in identical relation to said perforation in another portion of said emulsion, developing, fixing, and transforming the rst innige to a dye image and the second image to a complementary colored image, said images together subtractively reproducing color.

26. As a new article of manufacture a support carrying a colloid emulsion carrying in one portion a bleached dye absorbent image and in another portion a black silver image.

27. As a new article of manufacture a su pport carrying in one portion a bleached image absorbent to acid dyes, and in another portion a black silver image.

28. As a new article of manufacture a support carrying a hardened colloid emulsion carrying in one portion a bleached dye :ibsorbent image. and in another portion a black silver image.

29. As a new article of manufacture, a supporrl carrying in a single colloid emulsion two photographic images, one being a bleached image absorptive to dye, and the other being a black silver image.

30. As a new article of manufacture, a support carrying in a sin le hardened colloid emulsion two photoerap iic images, one being a bleached image a sorptive to dye, and the other being a black silver image. y

31. As anew article of manufacture, a su iport carrying in a single hardened colloid emulsion two photo rapliic images, one being a bleached image a sorptive to an acid dye, and the other being a black silver image.

32. As a new 'article of manufacture, a support carrying in a single colloid emulsion superimposed registering photographic iinages, one being a bleanced image absorptii'e to dye, and the other being a black silver image.

33. As a new article of manufacture, a support carrying in a single hardened colloid emulsion superimposed registering photographic images, one being a bleached image absorptive to dye, and the other being a black silver image.

34. As a new article of manufacture, a support carrying in a single colloid emulsion superimposed registering photo raphic images, one beinga bleached image a sorptive to an acid dye, and the other being a black silver image.

35. As a new article of manufacture, a support carrying in a single hardened colloid emulsion superimposed registering vphotolll() emulsion two photographic images, one being .salt of copper and chromium impregnated with an acid dye and the other comprising a transparent diiferently colored salt of a metal. f

39. As a new article of manufacture, a support carrying in a single colloid emulsion two photographic images, one being a transparent bleached image absorptive to dye, andthe other being a black silver image.

40. As a new article of manufacture, a support carrying in a single colloid emulsion 'two photographic images, one being' a transparent .bleached image absorptive to an acid dye, and the other being a black silver image.

41. A subtractive two color transparency composed of a transparent support provided with an elongated edge perforation and having a single coating on one side having in one stratum thereof a dye image and in another stratum a. second image in color complementary thereto, both of said images being registered in the same relation to said perforation.

42. A motion picture strip film having on each image area a plurality of registered color value images colored in complementary colors, at least one of said images being conlposcd of a. transparent silver free compound of a metal colored with an acid dye.

43. A motionpicture strip film having on each image area a plurality of registered color value images colored in complementary colors, at least one of said images comprising a transparent copper compound colored with an acid dye.

44.-. In the process of producing two images 1n a single layer of colloid emulsion by successive rintings with intermediate development o the first image, increasingthe sensitiveness for the second print hy treatment in a suitable bath.

4.5. In the process of producing two images in a single layer of colloid emulsion by suc- 'cessive printings with intermediate development of the first image, increasing the sensitiveness for the second print by treatment in a bath containing a bromid.

46. In the process of producing two. images in a single layer of colloid emulsion by successive printings with intermediate development and conversion of the first image, reviving the speed for the second print by treatnient in a hath containing a broniid;

47. In the process ot producing two images 'in a single layer of colloid emulsion by successive printings with intermediate development and conversion of the first image, increasing the sensitiveness for the second print by treatment in a suitable bath.

4S. As an article of manufacture, a support carrying a colloid emulsion containing in one port-ion a developed silver image, and a residual revived sensitive portion.

49. As au article ot manufacture, a support carrying a colloid emulsion containing in one portion a developed converted and dye absorptive image, and a residual sensitive portion.

Signed at New York, in the county of New York and State of Newy York, this 18th day of May, A. D. 1920.

WILLIAM V. D. KELLEY.

Images