US3650752A

US3650752A - Whitened photographic printing paper

Info

Publication number: US3650752A
Application number: US36525A
Authority: US
Inventors: Hiroyuki Amano; Nobuo Tsuji; Takushi Miyazako; Kazuo Shirasu; Yosinori Tutiya
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1969-05-12
Filing date: 1970-05-12
Publication date: 1972-03-21
Anticipated expiration: 1989-03-21
Also published as: DE2023151C3; DE2023151B2; GB1273085A; DE2023151A1

Abstract

A photographic printing paper comprising a support having thereon a light-sensitive silver halide emulsion layer containing a water-soluble fluorescent brightening agent and a partially urethanated polyvinyl alcohol having the following recurring structure: WHEREIN X+ Y IS A NUMBER FROM 100 TO 5,000 AND Y/(X+ Y) IS A NUMBER FROM 0.05 TO 0.25.

Description

United States Patent Amano et al.

[451 Mar. 21, 1972 WHITENED PHOTOGRAPHIC PRINTING PAPER Inventors: Hiroyuki Amano; Nobuo Tsuji; Takushi Miyazako; Kazuo Shirasu; Yosinori Tutiya, all of Kanagawa, Japan Assignee: Fuji Photo Film Co., Ashigara-Kamigun,

Kanagawa, Japan Filed: May 12, 1970 Appl. No.: 36,525

Foreign Application Priority Data May I2. 1969 Japan ..44/36404 [1.8. CI ..96/82, l17/33.5 T, 96/85 Int. Cl ..G03c l/92 Field of Search ..96/82; 117/315 T Primary Examiner-Ronald H. Smith Attorney-Sughrue, Rothwell, Mion, Zinn and Macpeak [57] ABSTRACT A photographic printing paper comprising a support having thereon a light-sensitive silver halide emulsion layer containing a water-soluble fluorescent brightening agent and a partially urethanated polyvinyl alcohol having the following recurring structure:

wherein x+y is a number from 100 to 5,000 and y/(x+y) is a number from 0.05 to 0.25.

14 Claims, 1 Drawing Figure Patented March 21, 1972 m w w w w n C6255 53553; 22 5:

INVENTORS HIROYUK! AMANO NOBUO TSUJI TAKUSHI MIYAZAKO KAZUO SHlRASU YOS|NOR| TUTIYA M Zia,

ATTORNEYS WHITENED PHOTOGRAPI-IIC PRINTING PAPER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to photographic printing paper having an improved whiteness and, more particularly, photographic printing paper of improved whiteness achieved by incorporating a fluorescent brightening agent and a partially urethanated polyvinyl alcohol in the photographic printing paper to increase the fluorescent brightening action.

2. Description of the Prior Art It is known as a means for whitening a photographic printing paper to incorporate in the photographic emulsion layer or a subsidiary layer such as a protective layer, an intermediate layer, an undercoating, or a baryta layer, a fluorescent brightening agent emitting from violet to blue fluorescence when irradiated by ultraviolet light.

However, since fluorescent brightening agents have a dyeing affinity directly to fibers, etc., they show less of a dyeing affinity to the binders for the photographic emulsion layers or subsidiary layers, such as gelatin, and thus there is the disadvantage that the greater part of the fluorescent brightening agent is diffused in a conventional whitened photographic printing paper during photographic processing and washing, whereby the brightening effect is lost.

Therefore, in order to solve this problem, various investigations have been undertaken for increasing the brightening effect by using combinations of fluorescent brightening agents and various kinds of high molecular weight compounds. For instance, since a fluorescent brightening agent has a low dyeing affinity to gelatin, there have been provided various methods of dyeing gelatin with a fluorescent brightening agent including preliminarily dispersing in the gelatin polyvinyl pyrrolidone or poly-N-vinyl-S-methyl-2-oxazolidinone (US. Pat. No. 3,269,840), which has a good dyeing affinity to the fluorescent brightening agent. However, even if such high molecular weight compounds are used, the dyeing of the fluorescent brightening agent is insufficient and the agent is also diffused during photographic processing and washing. Further, such high molecular weight compounds show a higher brightening effect as the molecular weight thereof is LII higher but if the degree of polymerization is increased, the

compatibility thereof with gelatin as a binder is reduced and phase separation results, and therefore the use of high molecular weight compounds having a high degree of polymerization is accompanied by such disadvantages that significant trouble occurs during the coating step in the preparation of photographic light-sensitive materials and even if the coating procedure can be practiced, the resulting surface is matted in the case of producing glossy photographic printing papers.

Also, there has also been proposed a method wherein a copolymer of N-vinylpyrrolidone and vinyl acetate, styrene, acrylate or methacrylate is used together with a fluorescent brightening agent (Japanese Pat. publication No. 22882/68). However, although the copolymer may withstand photographic processing and washing for a long time as compared with polyvinyl pyrrolidone having the same molecular weight as the copolymer, the compatibility of the copolymer with gelatin is lower than that of polyvinyl pyrrolidone with gelatin and thus the disadvantage of phase separation is more likely to occur and the surface of glossy photographic printing paper becomes more matted.

Still another proposed solution has been the use of a combination of an ethyl acrylate-vinyl isobutyl ether-styreneacrylic acid copolymer and a cumarinic oil-soluble type fluorescent brightening agent (Belgian Pat. No. 646,150). However, this combination has the disadvantage that while the copolymer may be sufficient from the point of view of preventing diffusion, the copolymer has a significantly less fluorescent brightening effect than polyvinyl pyrrolidone.

Therefore, an object of the present invention is to provide a photographic printing paper having improved whiteness.

Another object of the present invention is to provide a photographic printing paper containing a fluorescent brightening agent. A still further object of the present invention is to provide a photographic printing paper having an improved whiteness even after being subjected to various photographic processings. A still further object of the present invention is to provide a photographic printing paper having good whiteness and a good surface property.

SUMMARY OF THE INVENTION The above objects of the present invention can be achieved by incorporating in an emulsion layer or a subsidiary layer of a photographic printing paper a water-soluble fluorescent brightening agent and a partially urethanated polyvinyl alcohol having the following recurring structure:

H GONH:

wherein x+y=l00 to 5,000 and y/(x+y)=0.05 to 0.25

BRIEF DESCRIPTION OF THE DRAWING The figure represents the fluorescent intensity of printing papers produced according to the present invention in comparison to other printing papers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The term photographic printing paper" as used in the present specification, includes not only black and white photographic printing paper and color photographic printing paper but alsolight-insensitive positive material for diffusion transfer photographic processes. The term subsidiary layer" includes light-insensitive layers for photographic printing papers, such as a protective layer, an intermediate layer, and undercoating, a baryta layer and an image receiving layer for diffusion transfer photographic paper.

The desirable feature obtained by using the combination of a fluorescent brightening agent and a partially urethanated polyvinyl alcohol according to the present invention are shown below. 1. A remarkable brightening effect is obtained as compared with the case of adding the fluorescent brightening agent alone.

2. The partially urethanated polyvinyl alcohol of this invention shows a larger fluorescent brightening effect as the degree of polymerization thereof becomes higher as is the case with the known high molecular weight compounds such as polyvinyl pyrrolidone, poly-N-vinyl-S-methyl-2-oxazolidinon, N- vinyl pyrrolidone-vinyl acetate copolymer, N-vinyl pyrrolidone-acrylate copolymer, N-vinyl pyrrolidone-styrene copolymer, and N-vinyl pyrrolidone-methacrylate copolymer. However, as the compatibility thereof with gelatin is good when the degree of polymerization thereof is high, no trouble during the coating step in the production of photographic light-sensitive materials nor matting of the surface of glossy photographic printing papers occurs.

3. Since the partially urethanated polyvinyl alcohol of this invention has a better dyeing affinity to the fluorescent brightening agent than the above-mentioned known compounds as we ll as having a good dyeing affinity to gelatin, a larger fluorescent brightening effect can be obtained not only when the molecular weight thereof is the same as that of the above-mentioned known compounds but even when it is lower than the molecular weight of the latter compounds even after the photographic printing paper is subjected to photographic processing and-washing.

4. It is knowrrthat polyvinyl pyrrolidone is an effective medium for the polymer latex used as a baryta composition for photographic printing paper (Dutch Pat. publication No. 6,705,734) but the partially urethanated polyvinyl alcohol of this invention is also as effective as polyvinyl pyrrolidone.

It is desirable that the partially urethanated polyvinyl alcohol of this invention have a high urethanated ratio, but too high a urethanation ratio is undesirable since, as a result, the water-solubility thereof is reduced. Therefore, the urethanation ratio of the partially urethanated polyvinyl alcohol may vary from 5 to 25 percent and preferably from 7 to percent. Also, the degree of polymerization may vary from 100 to 5,000, and preferably from 1,500 to 3,000, referring to the expression x+y described above.

The partially urethanated polyvinyl alcohol may be readily prepared by the reaction of polyvinyl alcohol and urea. For instance, the compound prepared by heating polyvinyl alcohol and urea in formamide or dimethyl formamide to l00 C. is shown in Pat. publication No. Sho 37-l ,3886. Also, it may be prepared by the method disclosed in Pat. publication No. Sho 37692 and Pat. publication No. Sho 40-l8,863. However, the method ofpreparing the partially urethanated polyvinyl alcohol of this invention is not limited and any suitable method can be employed.

Typical examples of the partially urethanated polyvinyl alcohol according to the present invention are shown below: Compound 1. The 14 percent-urethanated product polyvinyl alcohol having a polymerization degree 2,400.

Compound 2. The polyvinyl alcohol 1,700.

Compound 3. The polyvinyl alcohol 2,400.

Compound 4. The 7 percent-urethanated product of polyvinyl alcohol having a polymerization degree of 2,400.

The amount added ofthe partially urethanated polyvinyl alcohol of this invention is influenced by the nature of the layer to which it is added but generally the amount may vary from I to 30 percent by weight, based on the weight of the binder of the layer, and preferably, from 5 to percent by weight.

Any suitable water-soluble fluorescent brightening agent having a property ofemitting from violet to blue fluorescence by absorbing ultraviolet rays may be used in this invention. Diaminostilbene type, benzidine type, triazole type, imidazole type, and imidazolon type water-soluble fluorescent brightening agents having direct dyeing affinity are known and these known fluorescent brightening agents can be preferably used in accordance with the present invention. Practical examples ofthese fluorescent brightening agents are shown below.

Diaminostilbene type fluorescent brightening agent:

of of 15 percent-urethanated product having a polymerization degree of of 13 percent-urethanated product having a polymerization degree N N X-j j-NH-Q-OH-OH-QNHI Tx, K sloma so Na wherein X, X, Y and Y each represents NHC,;H NHC H SO Na, OH, NH ---NHCH CH SO Na, OCH CH OH, or -OCH Benzidine type fluorescent brightening agent:

OH Ill 1? OH S OaNB. S OaNa wherein R and R each represents h, CH or OCH or COOH COOH wherein R and R each represents H, CH or OCH Triazole type fluorescent brightening agent:

I do Na ;;Na i

l l N sogNfl SO NtI imidazole type fluorescent brightening agent:

l r R N SO Na SO;Na N R1 wherein R each represents H, CH C H;,, -OCH,

or -SO Na and R each represents H, CH:, or CH CH OH. 7 A lmidazalon type fluorescent brightening agent:

NH NH SOJNB SO Na These fluorescen t brightening agents are sold under the trade names: Blankophor" (Bayer A. 0., Germany), Leucophor" (J. R. Geigy A. 0., Switzerland), Tinopal" (Sadoz A. 0., Switzerland), "Uvitex" (CIBA A. (L, Switzerland), Kayaphor" (Nippon Kayaku K. K.), Whitex" (Sumitomo Kagaku Kogyo K. K.), and YL" (Honshu Kagaku K. K.). FOr example, Blankophor B" and Leucophor B" are fluorescent brightening agents represented by formula (1) above and "Whitex R extra cone" is represented by formula (2) above.

Furthermore, the high molecular weight fluorescent brightening agents previously discovered by the same inventors may also be employed according to the present invention, i.e., the high molecular weight compounds having the repeating units represented by the following general formula (I) or l Rt (swag I I Rt wherein R, and R each represents a hydrogen atom, an alkyl p p fi rate of 150 g-/ to g S p Further. 1 ggroup having one to eight carbon atoms, an aryl group having six to 12 carbon atoms, a hydroxyalkyl group having two to four carbon atoms. substituted derivatives thereof, a sulfoalkyl group having one to four carbon atoms, or an alkali metal or ammonium salt thereof;

R represents a halogen atom.

R and R each represents a hydrogen atom, an alkyl group having one to 12 carbon atoms, a hydroxylalkyl group having one to 12 carbon atoms, a sulfoalkyl group or an alkali metal or ammonium salt thereof, an aralkyl group, an aryl group having six to 18 carbon atoms, a hydroxyl-, carboxylor sul fonic acidsubstituted derivative thereof, or an alkali metal or ammonium salt thereof, a cycloalkyl group having six to l0- carbon atoms or a substituted cycloalkyl group; A represents an alkylene group having four to flve carbon atoms or an alkylene group containing a heterocyclic atom or a heterocyclic atomic group; Y represents an alkylene group having two to carbon atoms or a substituted alkylene group, or an arylene. group having six to 18 carbon atoms or a substituted arylene p;

Z represents a divalent heterocyclic atom or a heterocyclic atomic group; and m is O or 1.

As the binder for forming an emulsion layer or a subsidiary layer of a photographic printing paper in this invention, gelatin is most generally used but synthetic high molecular weight compounds such as polyvinyl alcohol and polyvinyl acetal may be effectively used.

The fluorescent brightening effect achieved by the use of the fluorescent brightening agent and the partially urethanated polyvinyl alcohol according to this invention, and

also, the effect of preventing the fluorescent brightening agentfrom being diffused by photographic processing and washing according to the present invention are shown experimentally by the following examples, although the invention is intended to be limited to the same.

EXAMPLE 1 Compound 5 OH HO S 0 Na of Compound 1, 10 g. of Compound 2, and I0 g. of Compound 4 were added to the emulsions as prepared above to give Samples B, C and D, respectively. For comparison, 10 g. of polyvinyl pyrrolidone having a degree of polymerization of 2,400 was added to the same emulsion as above instead of the above-described compounds to give Comparison Sample E. These printing papers thus prepared were processed in a developer having the following composition and in a fixing solution having the following composition:

Developer Metal (trade name) 1.0 g. Sodium sulfite l5.0 g. Hydroquinone 4.0 g. Sodium carbonate l H O) 27.0 g. Potassium bromide l.3 g. Water to make I liter Fixing Solution Sodium thiosulfate 240.0 g. Sodium sulfite 15.0 g. Glacial acetic acid l3.3 g. Borax 7.5 g. Potassium alum l5.0 g. Water to make l liter After washing the printing papers thus processed with running water at 15 C., they are dried through a ferrotype.

The intensity of fluorescence of the printing papers thus processes was measured, the results of which are shown in the accompanying drawing, wherein the relationship between washing time (by hour) and the relative fluorescence intensity is shown. Measurements of fluorescent intensity were conducted at l, 5, l2 and 24 hours. The relative fluorescent intensity is shown by a relative value to the whiteness of the surface of printing paper itself which is assumed to be 25. In the figure, Curve A corresponds to Sample A; Curve B, Sample B; Curve C, Sample C; Curve D, Sample D; and Curve E, Sample E, respectively.

As is clear from the Figure, Samples B-D of the present invention had a higher fluorescence intensity than Control Sample A and Comparison E. Also, it was confirmed that the intensity of fluorescence was increased as the degree of polymerization of the water-soluble high molecular weight material increased and also as the urethanation ratio increased. Furthermore, the surface properties of the printing papers B-D of this invention were not reduced.

Almost the same results were obtained when Compound 1, Compound 2 or Compound 4 of this invention was used together with Blankophor EU? (trade name), Whitex BF (trade name), Kayaphor S" (trade name), Tinopal GS" trade name),

S O Na or Compound 6 NH NH SOggNa S 3N8 EXAMPLEZ EXAMPLE3 A blue-sensitive silver iodobromide emulsion containing a 10 l g. ofBlankophor BUP (trade name) and l g. of Comyellow coupler. 3, -dicarboxya-(4- pound 3 of this invention were added to 1 liter of a barytastearoylamidob enzyl)acetanilide was coated on a barytasolution having the following composition, and the mixture coated paper. The coupler was added to the silver halide was coated on araw paper at the rate of 100 g./m. emulsion as an alkaline aqueous solution thereof. Then, a green-sensitive silver chlorobromide emulsion containing a Buryla-gglufion magenta coupler, l-( 3-sulfo-4-phenoxyl )-3-stearoyl-5- Barium Sulfa 500 s pyrazolone and, further a red-sensitive silver chlorobromide 2:221 alum emulsion containing a cyan coupler, N-n-octadecyl-l-hydrox- Formal, (30%) ai y-4-sulfo-Z-naphthamide were coated thereon and finally a Watertu make lliter protective layer was formed on the red-sensitive layer. Onto the baryta-coated paper thus prepared was coated a The protective layer was formed by adding lOO ml. ofa l composition prepared by adding a hardening agent and a percent aqueous solution of a known fluorescent brightening wetting agent to a gelatino silver halide emulsion containing agent as shown in Example 1 or 100 ml. of 1 percent aqueous gelatin and pure silver chloride in a ratio of 10:4. solution of a high molecular weight fluorescent brightening when the pr g p p thus pr p d was pr ssed as in agent(Compound 7) having the following repeating unit Example l, the whiteness of the printing paper containing SO Na 0 Na Ii L 3 I IH I 1 I JOONa COONB to 1 kg. of a 4 percent aqueous gelatin solution followed by 40 Compound 3 in the baryta layer was not reduced by washing coating and drying, or further adding, together with the and the surface whiteness of the printing paper was better than fluorescent brightening agent. 200 ml. of a 4 percent aqueous the printing paper not containing the compound of this invensolution of high molecular weight compounds l, 2, or 3 of this tion. invention and 200 ml. of a 4 percent aqueous solution of The same resu ts ere obtained when Compound 1, Compolyvinyl pyrrolidone followed by coating and drying. pound 2, or Compound 4 was used instead of Compound 3 in The color photographic printing papers thus produced were i xample. developed in a developer containing a color developing agent,

N-ethyl-N-B-hydroxyethyl-p-phenylenediamine and after sub- EXAMPLE 4 jecting them to stop-fixing, washing, bleach-fixing, washing, A coating composition prepared by adding 0.5 g. of hardening, washing, and drying, the intensity of fluorescence Tinopal GS" (trade name) as a fluorescent brightening agent was measured for each paper, the results being shown in the and 12 g. of Compound 4 to l liter of a 5 percent aqueous following table. gelatin solution containing 0.1 g. of colloidal nickel sulfide RELATIVE FLUORESCENT INTENSITY OF COLOR PHBTCGRAPHIC PRINTING PAPER AFTER COLOR PROCESSING High molecular weight compound Polyvinyl Fluorescent brightening agent None Compd.1 ComptLZ Compd.3 pyrrolidone Leucophor B 26 72 69 72 57 25 71 68 71 25 71 68 71 55 24 70 67 70 53 24 70 67 69 53 21 68 67 68 49 22 68 67 68 51 Compound 7 77 77 77 As is clear from the above results, by using a combination of was coated on a baryta-coated paper. To the layer thus a known fluorescent brightening agent and the partially prepared was applied astripping layer consisting essentially of urethanated polyvinyl alcohol of this invention, very excellent sodium alginate to give an image-receivinglmaterial for a difbrightening effects could be obtained. Also, the surface of the 70 fusion transfer P g p P T 6 g i ing comparison printing paper containing pol vin l lid material was brought into intimate contact with a light-sensiwas matted and the image became opaque, while the printing tive material having a preliminary exposed silver halide emulpaper containing the fluorescent brightening agent and the i n l y m g and after im ng h n a el p r, partially urethanated polyvinyl alcohol showed no such y were Separated from each other after 30 minutesphenomenon. The whiteness of the highlight area of the positive image in the case of using Compound 4 and the fluorescent brightening agent according to the present invention was better than when no compound of this invention was employed. Also, the same results were obtained when Compound 1, Compound 2, or Compound 3 was used instead of Compound 4 in this example.

The amount of the fluorescent brightening agent to be added to the layer may vary from 1 to 20 mg. per 100 cm. of the layer.

What is claimed is:

1. A photographic printing paper comprising a paper support having thereon a light-sensitive silver halide emulsion layer containing a water-soluble fluorescent brightening agent and a partially urethanated polyvinyl alcohol having the following recurring structure:

H C ONHz CHzC C ONHz wherein x+y is a number from 100 to 5,000 and y/(x+y) is a number from 0.05 to 0.25.

3. The photographic printing paper as in claim 2 wherein said water-soluble fluorescent brightening agent and said partially urethanated polyvinyl alcohol are incorporated in said subsidiary layer which is a protective layer.

4. The photographic printing paper as in claim Zwherein said water-soluble fluorescent brightening agent and said partially urethanated polyvinyl alcohol are incorporated in a light-sensitive silver halide emulsion layer.

5. The photographic printing paper as in claim 2 wherein said water-soluble fluorescent brightening agent and said partially urethanated polyvinyl alcohol are incorporated in said subsidiary layer which is a baryta layer.

6. A photographic printing paper comprising a paper support having thereon a light-sensitive silver halide emulsion layer and a subsidiary layer, at least one of said layers containing a water-soluble fluorescent brightening agent and a partially urethanated polyvinyl alcohol having the following recurring structure:

wherein x+y is a number from 1,500 to 3:000 and y/(x+y) is a number from 7 to 20.

7. The photographic printing paper as in claim 6 wherein said water-soluble fluorescent brightening agent is a member selected from the group consisting of diaminostilbenes, benzidines, triazoles, imidazoles and imidazolones.

8. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 14 percent urethanated polyvinyl alcohol having a degree of polymerization of2,400.

9. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 15 percent urethanated polyvinyl alcohol having a degree of polymerization of 1,700.

10. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 13 percent urethanated polyvinyl alcohol having a degree of polymerization of 2,400.

11. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 7 percent urethanated polyvinyl alcohol having a degree of polymerization of2,400.

12. The photographic printing paper as in claim 6, wherein said layer further contains a binder, and wherein the amount of said partially urethanated polyvinyl alcohol in saidlayer varies from 1 to 30 percent, by weight, based on the weight of the binder in said layer.

13. The photographic printing paper as in claim I, wherein said layer further contains a binder, and wherein the amount of said partially urethanated polyvinyl alcohol in said layer varies from 1 to 30 percent, by weight, based on the weight of the binder in said layer.

14. The photographic printing paper as in claim 2, wherein said layer further contains a binder, and wherein the amount of said partially urethanated polyvinyl alcohol in said layer varies from 1 to 30 percent, by weight, based on the weight of the binder in said layer.

Claims

2. A photographic printing paper comprising a paper support having therein a light-sensitive silver halide emulsion layer and a subsidiary layer, at least one of said layers containing a waTer-soluble fluorescent brightening agent and a partially urethanated polyvinyl alcohol having the following recurring structure: wherein x+y is a number from 100 to 5,000 and y/(x+y) is a number from 0.05 to 0.25.
3. The photographic printing paper as in claim 2 wherein said water-soluble fluorescent brightening agent and said partially urethanated polyvinyl alcohol are incorporated in said subsidiary layer which is a protective layer.
4. The photographic printing paper as in claim 2 wherein said water-soluble fluorescent brightening agent and said partially urethanated polyvinyl alcohol are incorporated in a light-sensitive silver halide emulsion layer.
5. The photographic printing paper as in claim 2 wherein said water-soluble fluorescent brightening agent and said partially urethanated polyvinyl alcohol are incorporated in said subsidiary layer which is a baryta layer.
6. A photographic printing paper comprising a paper support having thereon a light-sensitive silver halide emulsion layer and a subsidiary layer, at least one of said layers containing a water-soluble fluorescent brightening agent and a partially urethanated polyvinyl alcohol having the following recurring structure: wherein x+y is a number from 1,500 to 3,000 and y/(x+y) is a number from 7 to 20.
7. The photographic printing paper as in claim 6 wherein said water-soluble fluorescent brightening agent is a member selected from the group consisting of diaminostilbenes, benzidines, triazoles, imidazoles and imidazolones.
8. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 14 percent urethanated polyvinyl alcohol having a degree of polymerization of 2,400.
9. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 15 percent urethanated polyvinyl alcohol having a degree of polymerization of 1,700.
10. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 13 percent urethanated polyvinyl alcohol having a degree of polymerization of 2,400.
11. The photographic printing paper as in claim 6 wherein said partially urethanated polyvinyl alcohol is 7 percent urethanated polyvinyl alcohol having a degree of polymerization of 2,400.
12. The photographic printing paper as in claim 6, wherein said layer further contains a binder, and wherein the amount of said partially urethanated polyvinyl alcohol in said layer varies from 1 to 30 percent, by weight, based on the weight of the binder in said layer.
13. The photographic printing paper as in claim 1, wherein said layer further contains a binder, and wherein the amount of said partially urethanated polyvinyl alcohol in said layer varies from 1 to 30 percent, by weight, based on the weight of the binder in said layer.
14. The photographic printing paper as in claim 2, wherein said layer further contains a binder, and wherein the amount of said partially urethanated polyvinyl alcohol in said layer varies from 1 to 30 percent, by weight, based on the weight of the binder in said layer.