DE1267548B - Photographic material - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

G 03 c

German class: 57 b -

1,267,548
P 12 67 548.8-51 August 23, 1965 May 2, 1968

The invention relates to a photographic material containing an optical brightener.

Photographic copy papers are known which are whiter and lighter for better reproduction Image areas contain fluorescent compounds or so-called optical brighteners. Also was already proposed to use optical brighteners in high-boiling solvents such as dibutyl phthalate dissolve and introduce them into the photographic material in the form of these solutions.

The invention is based on the object of developing a photographic material that contains the same amount of fluorescent compound shows a stronger brightening: Such advantageous brightening effects are obtained when the optical brighteners are dispersed in certain amides in the photographic material, with the ratio of amide to optical brightener is preferably chosen so that the amide is present in large excess.

The photographic material of the invention is characterized in that in one of its colloid layers a dispersion of an optical brightener in a water-insoluble, organic amide low molecular weight with a boiling point above about 165 C.

It has proven to be particularly advantageous, as amides, those of the formula

Photographic material

R ₁ CN

to use, in which: Ri is an alkyl group with preferably 6 to 20 carbon atoms, an aryl group, e.g. B. a phenyl group or Naphlhylgruppe, or an aralkyl group, R ^ and R _{: i} hydrogen atoms, alkyl groups with preferably 1 to 4 carbon atoms, aryl groups, especially phenyl groups or aralkyl groups, the sum of the carbon atoms in the groups Ri, Ro and Rj at least 6, preferably at least 14. Particularly good results are achieved when the sum of the carbon atoms is 25 or 30. However, amides in which the sum of the carbon atoms present in the groups Ri, Ro and R;) is even higher, ie about 50, can also be used.

Ks was found to disperse in these amides fluorescent compounds brighten the pholographic material far more than if they did Applicant:

Eastman Kodak Company,

Rochester, N. Y. (V. St. A.)

Representative:

Dr.-Ing. W. Wolff, H. Bartels, Dipl.-Chem. Dr. J. Brandes and Dr.-Ing. M. hero, Patent Attorneys, 8000 Munich 22, Thierschstr. 8th

Named as inventor:

John Hamilton Van Campen,

Roger Byron Clark, Rochester, N.Y. (V. St. A.)

Claimed priority:

V. St. v. America August 24, 1964 (391 786)

the fluorescent compounds are dispersed in the solvents used since then, so that an excellent reproduction of white and brightest image areas is achieved. The photographic The material of the invention also has the advantage that the brightener in one of several layers existing photographic material does not migrate from one layer to the other, but into the Layer remains in which the dispersion is distributed. Also, the brightener is used during the development process not depleted.

A three color printing material was used in the following examples. The photographic material each time had the same composition and differed only in that that in the red-sensitive Emulsion layer introduced dispersion of a blue-green dye forming Coupler was changed. The color photographic material consisted of a support Paper on which the following layers were arranged:

Layer 6: gelatin layer,

Layer 5: a blue-green dye forming, a red-sensitive silver halide emulsion layer containing a phenolic coupler,

Layer 4: gelatin layer,

809 574-384

Layer 3: a-purple dye forming, green-sensitive silver halide emulsion layer containing a pyrazolone coupler.

Layer 2: gelatin layer,

Layer 1: a yellow dye-forming acylacetanilide coupler containing blue-sensitive silver halide emulsion layer.

example 1

A solution of 2.52 g of a blue-green dye forming phenolic coupler in 5.04 ml of diethyl lauramide was prepared. One of the couplers described in U.S. Pat. No. 2,801,171 under No. 3, 4, 5 or 6 was used as the coupler. This solution was then dispersed in an aqueous solution containing 5.58 g of gelatin and about 0.1 g of sodium triisopropylnaphthalene sulfonate as a wetting agent. The resulting mixture was passed through a colloid mill five times, whereupon the weight of the resulting dispersion was brought to 126 g by the addition of water and added as a blue-green dye-forming coupler dispersion to the red-sensitive emulsion (layer 5). The emulsion was applied in a layer thickness such that there were 35 mg of coupler ^{per 929 cm 2.}

Example 2

The procedure described in Example 1 was repeated, but instead of diethyl lauramide Dibutyl phthalate is used.

B e i s ρ i e 1 3

The procedure described in Example 1 was repeated, but 0.36 g of 3- (phenyl) -7- (2- [dimethylaminoethyl] ureido) coumarin were dispersed in the diethyl lauramide together with the coupler. The emulsion was applied in a layer thickness such that 5 mg of the brightener was applied to an area of 929 cm ² (layer 5).

Example 4

The procedure described in Example 3 was repeated, but instead of 5.04 ml of diethyl lauramide 10.08 ml used.

Example 5

The procedure described in Example 3 was repeated, but instead of diethyl lauramide Dibutyl phthalate is used.

Example 6

The procedure described in Example 4 was repeated, but here too, instead of diethyl lauramide Dibutyl phthalate is used. Samples of the photographic materials prepared were exposed on a sensitometer with an intensity scale and according to the usual method containing color couplers standard color development processes applied to photographic materials. The one with it The results obtained are summarized in the following table:

solvent

Diethyl lauramide ..
Diethyl lauramide. .
Diethyl lauramide ..
Dibutyl phthalate.
Dibutyl- ■ 5 phthalate ..
Dibutyl phthalate.

Quantity ratio
solvent
/ u brightener

without brightener

14: 1

28: 1
without brightener

14: 1

28: 1

Relative
Specular
lelligkeil Relative
spectral
fluoroczen / 69.0 2.0 69.6 23.8 72.3 38.2 69.0 2.0 69.6 9.8

69.4

13.0

The relative spectral brightnesses given in the table were determined by irradiating the samples with non-disperse white light by measuring the energy emitted and the energy reflected by the samples. To determine the relative spectral fluorescence, samples were irradiated with UV light (365 Hg line) and the emitted energy was measured monochromatically in the visible range of the spectrum. (The brightener absorbs UV radiation and re-emits the light energy in the blue area of the spectrum.) An increase in the relative spectral brightness by even small amounts is noticeable in a much improved brightness of the white and brightest image areas.
The results compiled in the table show the excellent results obtained with diethyl lauramide. The results are all the better, the greater the excess • of diethyl lauramide over the optical brightener. An increase in the relative spectral brightness of 3 divisions is achieved if the ratio of diethyl lauramide to brightener is 28: 1. The effects achieved according to the invention cannot be achieved with the previously used dibutyl phthalate. The results compiled in the table also show that when diethyl lauramide is used instead of dibutyl phthalate as the solvent, the relative spectral fluorescence is also quite decisively improved. Equally good results are obtained if other amides of the formula given are used in place of diethyl lauramide, such as, for. B. caprylamide, capramide. Lauramide. Myristamide. Palmitamide. Stearamide. The N-monoalkyl- and NN-dialkyl-substituted amides, such as, for. B. N-butyl caprylamide. NN-dipropylcapramide. N-methyl lauramide. NN-dibutyl myristamide. NN-dipropylpalmitamide and NN-dimethylstearamide.
Practically all of them are known as optical brighteners.

f ¹⁰ th water-insoluble organic brighteners suitable, such as. B. Benzidines. Coumarins. Stilbene. Benzimidazoles. Benzoxazoles or pyrazolidones. The brighteners described in British patent specification 786 * 234, the 7-aminocoumarins, have proven to be particularly suitable. especially the 7-ureidocoumarin. proven.

It has proven advantageous to have a weight ratio of solvent to brightener of

at least 10: 1, preferably from at least 20 to 25: 1, to be used. If necessary, can the ratio of solvent to optical brightener can also be much greater, e.g. B. 50: 1, 100: 1 or even greater.

According to the invention, the brightener dispersions can be used in black-and-white photographic material housed in the emulsion layer or in a colloid layer separate from the emulsion layer will. However, their use has proven to be particularly advantageous in color photography Material proven. They can be housed here in any colloid layer. In the case of color photographic material with separate red, green and blue sensitive emulsion layers, which contain a cyan, a magenta and a yellow dye-forming coupler, the brightener dispersion in any colloid layer, preferably in the outermost, can be a color coupler containing layer. It has also proven advantageous to use the brighteners to disperse in a layer of the color photographic material containing a color-forming coupler contains, which forms a dye when developing, which interacts with the brightener in the way. that the fluorescence is extinguished in the places where the dye was formed. Photographic Material of this type has the great advantage of having a particularly good degree of whiteness in the areas where no dye was developed. It also exhibits good brightness in the brightest areas of the image and does not exhibit the undesirable blue sheen that some color photographic materials do have that contain optical brighteners in the carrier material.

The phenol and naphthol couplers forming a blue-green dye are, for example, couplers, form the dyes, which can interact with the brighteners and the fluorescence just extinguish in the places where the dye is developed. Particularly suitable, a blue-green one Dye-forming phenol couplers are given in U.S. Patents 2,423,730 and 2,801,171 described.

The brightener dispersions are in the hydrophilic colloid layers of photographic materials, which, as mentioned, may contain silver halides, embedded. The ones in the U.S. Patent 3,039,873 at column 3, lines 41 to 67, of the hydrophilic colloids described.

The brightener dispersions can also be introduced into hydrophilic layers as scintillating layers can be used in electron beam direct recording films. Such layers can thereby above or below the silver halide emulsion layer or on the opposite side of the emulsion layer Be arranged side of the carrier.

Claims (6)

Patent claims: 1. Photographic material with at least one light-sensitive, optionally color coupler containing silver halide emulsion layer and optionally a further hydrophilic layer Colloid layer, an optical brightener being dispersed in at least one layer is, characterized in that the dispersion of the in one of the colloid layers optical brightener in a water-insoluble, organic amide of low molecular weight is distributed with a boiling point above 165 C. 2. Photographic material according to claim 1, characterized in that it is used as a solvent for the optical brightener contains an amide of the following formula: R ₁ CN where: Ri is an alkyl, aryl or aralkyl group and R> and R _{: i are} hydrogen atoms, alkyl, aryl or aralkyl groups, the sum of the carbon atoms in the groups Ri, Ro and Rn being at least 6. 3. Photographic material according to claims 1 and 2, characterized in that the ratio of amide to optical brightener is at least 20: 1. 4. Photographic material according to claims 1 to 3, characterized in that the solution of the brightener is dispersed in the silver halide emulsion layer. 5. Photographic material according to claim 4, characterized in that in the silver halide emulsion layer a solution of a 7-ureidocoumarin derivative in diethyl lauramide is dispersed. 6. Photographic material according to claims 1 to 4, characterized in that the material is a multilayer color photographic material in which the solution of the " Brightener is dispersed in the red-sensitive layer. Considered publications:
German interpretative document No. 1 150 274. 809 574/384 4.68 Q Bundesdruckerei Berlin