Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Electron beam imaging
Reexamination Certificate
2000-12-29
2002-07-30
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Electron beam imaging
C430S270120, C430S270140, C430S295000, C430S934000, C430S942000, C430S945000
Reexamination Certificate
active
06426172
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general to photography and in particular to a novel processed motion picture print film photographic element. More specifically, this invention relates to a motion picture print film which is processed after exposure thereof to result in a retained silver halide level of at least 100 mg/M
2
, which processed print film is capable of being marked with a laser with improved performance.
BACKGROUND OF THE INVENTION
Marking of photographic film elements to provide, e.g., graphic elements, characters, bar codes or text is often desired in the photographic art. The showing of foreign language films in a motion picture theater, e.g., typically includes the simultaneous display of the translated dialogue in the form of marked subtitles along with display of the film scenes. A current frequently used method of subtitle marking, described in U.S. Pat. Nos. 4,854,696 and 5,367,348, involves embossing or etching the subtitle text into the film's photographic emulsion image layer(s), after imagewise exposure of the film scenes and photographic processing to develop the imagewise exposed scenes. Marking is currently frequently done by laser ablation, wherein a laser beam of high energy travels along a determined path corresponding to the inscriptions to be formed on the film element. The majority of laser subtitling labs use an Argon laser with peak emissions at 488 and 514 nm. In such method, the photographic emulsion layer(s) coated onto the film support becomes ablated locally. Photographic color films comprise image dye-forming emulsion layers coated on a transparent support, and the marked or ablated areas comprise clear or low density areas surrounded by the unmarked dye-containing image areas. Similarly, for black and white films the marked or ablated areas comprise clear or low density areas surrounded by the unmarked image areas which contain silver metal. In the particular application of laser subtitling of photographic films, the quality of laser marked subtitles is dependent upon the density and color differences between the marks and the surrounding dye or silver image areas, and on the wavelength, power, and writing speed of the laser. The power and speed are selected to remove as much of image emulsion layers as possible without damaging or distorting the support. Laser subtitling is typically performed on the final color or black and white release print film intended for projection in a theater, but may also be performed on color intermediate or black and white films to form subtitle images which may then be optically printed onto another intermediate or black and white film to form a negative image, which may then be printed onto the final release print film.
Most laser subtitling systems were originally designed and optimized for marking motion picture films having acetate film base supports. A switch in the industry from acetate to polyester supports for motion picture print films has required the subtitling labs to make changes in their operations to reoptimize results, which has been a problem as thermoplastic polymer support materials, such as polyester, are more succeptible to support damage. There is an inherent conflict between using sufficient power to mark in low density image areas without causing significant base damage in the high density image areas, as due to the non-uniform release of gelatinous residues or to the damage of the support, undesired dark and/or colored spots may be observed when the film image is enlarged and projected on the screen in a theater, especially for print films having polyester film supports.
After imagewise (scene) exposure, silver halide motion picture photographic elements are typically processed using standard photographic processing procedures, such as Process ECP-2B for color print films, standard D-97 processing for black and white films, and ECN-2 for color negative and intermediate films. In such standard processes, residual (or retained) silver halide is typically minimized after image development to prevent the appearance of the developed image from changing, as such residual silver halide may be slowly photoreduced to silver metal. Silver salts are typically removed in a “fix” step or steps, wherein they are solubilized by complexation with a silver ligand. Where silver metal formed during image development is also desired to be removed (typically for color films where the image is formed with dyes), it is oxidized and converted back to a silver salt in a “bleach” step (optionally with a bleach accelerator), and then removed in a fix step. Alternatively, the bleach and fix may becomed into a single bleach-fix or “blix” step. Standard process ECP-2B for color print films, e.g., comprises prebath (10″), water rinse (20″), color developer (3′), stop bath (40″), first wash (40″), first fix (40″), second wash (40″), bleach (1′), third wash (40″), second fix (40″), fourth wash (1′), and final rinse (10″) steps, and then drying with hot air. Typical levels of retained silver in normally processed color print films in areas of high density are less than 150 mg/m
2
, and the typical level of retained silver halide in normally processed films is less than 50 mg/m
2
.
It would be desirable to provide a method for photographic processing and laser marking an imagewise exposed motion picture photographic film element in order to provide improved performance when the processed photographic film is marked by means of a laser beam.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a method for processing and laser ablation marking an imagewise exposed motion picture photographic film element which comprises a support having on a front side thereof one or more image-forming units comprising at least one light-sensitive silver halide emulsion layer, comprising processing the film to provide a developed photographic image with at least 100 mg/m
2
of retained silver halide, and subsequently laser ablation marking the film to selectively ablate portions of the image forming units from the support.
DETAILED DESCRIPTION OF THE INVENTION
Motion picture film photographic elements processed in accordance with the invention comprise a support having on a front side thereof at least one silver halide emulsion layer. In preferred embodiments, the elements may include an antihalation undercoat in a subbing layer unit between the support and the silver halide emulsion layer(s), an outermost protective overcoat layer, an antistatic layer on either side of the support, and an outermost protective backcoat layer on the back side of the support.
While standard photographic processing is designed to minimize levels of retained silver halide in a processed photographic film, motion picture films are deliberately processed in accordance with the invention to result in a developed photographic image with at least 100 mg/m
2
of retained silver halide, preferably from 100 to 1000 mg/m
2
, more preferably from 100 to 500 mg/m
2
and most preferably from 100 to 250 mg/m
2
of retained silver halide. Such levels of retained silver halide have surprisingly been found to result in improved performance when the processed films are subsequently laser ablation marked to selectively ablate portions of the image forming units from the support. Retained silver halide levels of less than 100 mg/m
2
have little impact on laser ablation marking performance, while levels above 1000 mg/m
2
, may adversely effect minimum density and hues of the developed images. The most preferred range of 100 to 250 mg/m
2
of retained silver halide provides optimum laser marking performance while minimizing impact on minimum density and hues of the developed images.
Special image processing techniques are known in the art which are designed to specifically retain a significant amount of silver metal (e.g., greater than 100 mg/m
2
, or even greater than 500 mg/m
2
) during the processing of color photographic silver halide pr
Enon Alain M.
Gisser Kathleen R.
Kestner Diane E.
Anderson Andrew J.
Eastman Kodak Company
Le Hoa Van
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