US2571725A

US2571725A - Eliminating stain in photographic color material

Info

Publication number: US2571725A
Application number: US690720A
Authority: US
Inventors: Donald B Kimball; Wendell H Mcdowell
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1946-08-15
Filing date: 1946-08-15
Publication date: 1951-10-16
Anticipated expiration: 1968-10-16

Description

1951 D. B. KIMBALL ETAL 2,571,725

ELIMINATING STAIN IN PHOTOGRAPHIC COLOR MATERIAL Filed Aug. 15, 1946 YELLOW FILTER LAYER l4 A EMULSION LAYERS l3 i CONTAINING COUPLERJ /Z BARYTA LAYER CONTAINING A JUL F/TE 0R B/SULF/TE m SUPPORT DONALD E KIMBALL TAEVDELL H. M DOWELL INVENTORS A TTORNEYS Patented Oct. 16, 1951 ELIMINATING STAIN IN PHOTOGRAPHIC i COLOR MATERIAL Donald B. Kimball and Wendell H. McDowell, .Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application August 15, 1946, Serial No. 690,120.

This invention relates to photography-and. particularly to a method of eliminating stain in photographic color material.

In the production of colored images in photographic emulsions containing color-forming compounds, the composition of the support material, especially paper, affects thequality and stability of; the colored images. For example, photographic paper frequently contains formaldehyde which is used in the production of the paper, and this may cause stain or otherwise adversely affect the photographic emulsion. coated on thepaper support. Loss in emulsion density may also be caused for this, or other reason.

It is therefore an object of the present invention to provide a method for eliminating stain and emulsion density loss in photographic emulsions containing color-forming compounds. A further object is to provide a method of preventing color falsification or degradation, and to preserve proper color rendition, in a photographic element having emulsions containing color-forming compounds. A still further object is to provide a method for overcoming the adverse efiect of formaldehyde on photographic color emulsions. Other objects will appear from the following description of the invention.

These objects are accomplished by incorporating in a layer of the photographic element, such :as a baryta layer on paper, an alkali metal sulfite or bisulfite or an aldehyde bisulfite. The ;sulfite or bisulfite may also be incorporated in the support material itself or in a backing layer or intermediate layer of the photographic ele- :ment.

vention, photographic paper stock, which may or may not contain an aldehyde having adverse effect on the color-forming emulsion layers coated on the support, is coated with a baryta layer containing an alkali metal sulfite or bisulfite or an aldehyde bisulfite. A subbing layer or layers may then be applied, if desired, followed by one or more silver halide emulsion layers containing color-forming compounds.

The compounds used in the baryta coating may consist of an alkali metal sulfite or bisulfite such as sodium, potassium or ammonium sulfite or bisulfite or an aldehyde bisulfite such as acetal dehyde bisulfite. The aldehyde combined with the bisulfite is not in free form and, therefore, does not adversely affect the color-forming emulsion layer.

2 Claims. (01. 95 s) The sulfites or bisulfites may be incorporated in the paper itself or in a backing layer or an intermediate layer of the photographic element. They may also be applied to elements having supports other than paper, such as cellulose esters or synthetic resin supports. V

The color-forming compounds incorporated in the emulsion layer or layers of the photographic element may include any of the known coupler compounds such as those described in Vittum; Peterson and'Porter, U. S..Patents Nos. 2,271,238;

2,362,598; and 2,353,205; WeissbergerU. S. Patent No. 2,298,443 and Salminen, Weissberger and Glass U. S. Patent No. 2,313,586. In the case of multi-layer coatings the emulsion layers are usually coated with the red sensitive layer containing the cyan coupler nearest the support, the green sensitive layer containing the magenta layer next, and the blue sensitive layer containing the yellow coupler outermost.

Upon storage of a multi-layer photographic paper containing couplers producing yellow, magenta, and cyan dye images, there is a tendency for a loss of yellow emulsion density, and there is also a propensity towards cyan dye stain. The sulfites and bisulfites which we propose to use prevent loss of yellow emulsion density and also prevent the formation of cyan or yellow dye stain.

Our invention will be illustrated by reference to the following example.

To pounds of baryta formula containing 39% solids there were added 112 grams of sodium bisulfite. This combination was coated on photographic paper stock so as to obtain 0.2 gram of bisulfite per square meter of paper when the total weight of coating was 30 grams per square meter. Following this a coating of about 25 grams per square meter of baryta was applied from a formula containing no sodium bisulfite. By applying the baryta in two layers the advantages of the sulfite were achieved and better adhesion of the emulsion layers was obtained. The usual emulsion layers containing couplers were then applied, and it was found that the material had high stability to heat and moisture when compared with similar products containing no bisulfite.

While this coating contained 0.2 gram of sodium bisulfite per square meter of surface, it was found that amounts as low as 0.05 gram per square meter of surface were effective in improving the emulsion stability. Amounts greater than 0.2 gram per square meter of surface can, of course, be used but higher amounts of bisulfite tend to decrease the adhesion of the emulsion layers to the support.

In the accompanying drawing which illus- '='trate the preferred form of our invention in :sectional view, is a support of paper or other material which may or may not contain form- :aldehyde, II is a baryta layer containing the :alkali metal sulfite or bisulfite or the aldehyde bisulfite, followed by the customary emulsion layers l2, l3 and I4 containing coupler or color- Iforming compounds. layer is coated between the layers l3 and M.

The sulfites may also be incorporated in the :support or the baryta layer of a photographic 'element not containing couplers, in order to pre- '-.vent loss in emulsion density.

It will be understood that the examples and Imodifications discussed herein are illustrative only, and that our invention is to be taken as Ilimited only by the scope of the appended claims.

What we claim and desire to secure by Letters Patent of the United States is:

VI. A photographic element comprising a paper support having thereon at least one silver halide emulsion layer containing a color former capable of reacting with the development product of a primary aromatic amino developing agent to produce a dye image in said emulsion layer, a paper support containing an aldehyde tending to react to produce color fog and a baryta layer between said paper support and said emulsion layercontaining an alkali metal sulfite acting to prevent -formation of color fog.

The usual yellow filter' 2. A photographic element comprising a paper support having thereon at least one silver halide emulsion layer containing a color former capable of reacting with the development product of an aromatic amino agent to produce a dye image in said emulsion layer, a paper support containing an aldehyde tending to react to produce color fog and a baryta layer between said paper support and said emulsion layer containing sodium bisulfite acting to prevent formation of color fog. DONALD B. KIMBALL.

WENDELL H. McDOWELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,763,533 Miller June 10, 1930 1,954,452 Mannes et a1. Apr. 10, 1934 2,304,940 Mannes et al. Dec. 15, 1942 2,309,492 Albers et al Jan. 26, 1943 2,360,290 Vittum et al. Oct. 10, 1944 FOREIGN PATENTS Number Country Date 13,835 Great Britain of 1907 OTHER REFERENCES British Journal of Photography, vol. 75. Mar. '23, 1928, pp. 172-173.

Claims

1. A PHOTOGRAPHIC ELEMENT COMPRISING A PAPER SUPPORT HAVING THEREON AT LEAST ONE SILVER HALIDE EMULSION LAYER CONTAININIG A COLOR FORMER CAPABLE OF REACTING WITH THE DEVELOPMENT PRODUCT OF A PRIMARY AROMATIC AMINO DEVELOPING AGENT TO PRODUCE A DYE IMAGE IN SAID EMULSION LAYERS, A PAPER SUPPORT CONTAINING ALDEHYDE TENDING TO REACT TO PRODUCE COLOR FOG AND A BARYTA LAYER BETWEEN SAID PAPER SUPPORT AND SAID EMULSION LAYER CONTAINING AN ALKALI METLA SULFITE ACTING TO PREVENT FORMATION OF COLOR FOG.