Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Antihalation or filter layer containing
Reexamination Certificate
2001-10-01
2003-04-22
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Antihalation or filter layer containing
C430S510000, C430S517000, C430S527000, C430S529000, C430S530000, C430S961000
Reexamination Certificate
active
06551769
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a photographic film material comprising on one side of a support material, a conductive subbing layer providing permanent antistatic properties and on the opposite side of the support, a backing layer providing suitable scratch resistance.
More specifically the said photographic film is especially suitable for use as a motion picture color print film.
BACKGROUND OF THE INVENTION
Silver halide photographic motion picture used as print films for movie theater projections have since quite a long period of time made use of a layer containing “carbon black” on the side opposite to the light-sensitive side of the film. This backing layer thereby provides both antihalation protection and antistatic properties.
“Carbon black”, is applied in a alkali-soluble binder thus allowing the layer to be removed by a processing step involving soaking of the film material in an aqueous alkaline solution, followed by scrubbing the backside layer and rinsing with water. This “carbon black removal” takes place prior to image development and is both tedious and environmentally undesirable since large quantities of water are utilized. Moreover in order to facilitate removal during film processing, the backing layer containing carbon black is not made highly adherent to the photographic film support and may dislodge during various film manufacturing operations or manipulations, such as during film slitting and film perforation. Carbon black debris generated during these operations may become lodged on the photographic emulsion and may cause image defects during subsequent exposure and film processing.
After removal of carbon black the antistatic properties of the processed film material are lost. Undesired static charge build-up may thus occur on the motion picture print film when transported through projectors or on rewinding equipment. Although these high static charges cannot cause static marks on the processed photo-graphic element or material when discharging, the said high static charges may attract dirt particles to the film surface. Once deposited on the film surface, these dirt particles may create abrasion or scratches or, if sufficiently large, dirt particles may become visible and disturb the projected image, which may become very ennoying to the spectators. Conventional backing layers containing carbon-black are typically containing a lubricant therein or in an overcoat layer in order to improve conveyance during manufacturing operations or image exposure. After processing however the lubricant is removed together with the carbon black and, therefore, processed film has a high friction coefficient, measured on the side of the backing layers of the film, which is undesirable for good transport and film durability during repeated cycles through a movie theater projector.
Use in motion picture films of coatings having a layer containing carbon black on the side of the support opposite to the light-sensitive layers (therefore als called “backing layer”) has been described e.g. in U.S. Pat. Nos. 2,271,234 and 2,327,828.
An alternative for a backing layer containing carbon black has been proposed e.g. in EP-A 0 772 080 and the corresponding U.S. Pat. No. 5,679,505. Therein a photographic film has been described comprising a support having, in order, on one side thereof an antihalation undercoat and at least one silver halide emulsion layer and having on the opposite side thereof a permanent antistatic layer and a protective topcoat, wherein the protective topcoat is comprised of a polyurethane binder and a lubricant. However a disadvantage of such a polyurethane binder is the appearance of “tar adsorption” during processing. Therefore in several patent applications a topcoat has been described which is situated on top of the backing layer comprising the polyurethane binder in order to minimize the said “tar adsorption” (see e.g. U.S. Pat. Nos. 5,786,134; 5,910,399; 5,952,165; 5,962,207 and 5,928,848).
Another alternative has been proposed e.g. in EP-A 0 252 550 wherein a photographic film has been described comprising a transparent support having coated thereon, in succesion a blue-sensitive silver halide emulsion layer, a red-sensitive emulsion layer, an intermediate layer, a green-sensitive layer and an antistress layer wherein between the said support and the blue-sensitive silver halide emulsion layer a yellow antihalation undercoat has been provided which comprises at least one yellow non-diffusing dye absorbing blue light, wherein said dye is removable and/or decolorizable during processing, as well as between the blue-sensitive layer and the red-sensitive layer, where an bluish antihalation layer is present as an intermediate layer, said layer comprising at least one non-diffusing blue dye absorbing red light which is removable and/or decolorizable during processing.
The other side of the support has been provided with an antistatic layer comprising an electroconductive polymer such as polystyrene sulphonic acid sodium salt. A disadvantage of such a backing layer however is the poor abrasion resistance and durability for motion picture print film applications. In addition antistatic performance of these polymers is greatly reduced after processing.
As is well known subtitling may, in several countries wherein the mother tongue is differing from a world language, be an additional requirement. Such a subtitling of a processed motion picture print film can be performed by means of a laser beam of high energy. An optimized method of subtitling a motion picture film has been described e.g. in U.S. Pat. No. 5,367,348. As has been disclosed in said Application the method is well adapted to subtitle motion picture films on a support based on cellulose derivatives such as cellulose triacetate, but is equally applicable to film supports based on a thermoplastic polymer material such as polyester. However if use is made of a transparent polyester support such as e.g. polyethylene terephthalate, disturbing optical failures may occur.
As has been described in EP-A 0 782 045 addition of at least one light-stabilizer and at least one reducing agent in the antihalation undercoat provides better subtitling quality when performed by means of a laser beam on a motion picture print film coated on polyester.
A remaining disadvantage of that invention however is the fact that addition of these compounds to the antihalation undercoat, also comprising the antihalation dyes, makes the amount and load of organic substances in the antihalation layer become very large. As the weight ratio of organic substances to gelatin should be reduced in order to avoid physical disadvantages the required amount of gelatin coated in the antihalation undercoat becomes too large.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a photographic film material useful as a motion picture print film, without utilizing a backing layer containing “carbon black”, which does not show, after processing, the aforesaid problems of loss of conductivity and loss of durability, especially with respect to scratching stability.
It is a further object to provide a motion picture print film which can be subtitled by means of a laser and which provides high quality—good definition—of the figures, burned through the whole layer package of the color print material.
Further objects of the present invention will become apparent from the description hereinafter.
SUMMARY OF THE INVENTION
The above mentioned objects have been realized by providing a silver halide photographic film element comprising, on a light-sensitive side of a transparent polyester support, in order, an electrically conductive subbing layer, an antihalation undercoat, a light-sensitive emulsion layer or layer arrangement (optionally including one or more intermediate, non-light-sensitive layers between said emulsion layers) and a protective overcoat; and on a non-light-sensitive backing layer at the side opposite thereto, in order, a subbing layer containing a lubricant and a topcoat layer,
characterized
Andries Hartwig
Thillo Etienne Van
Viaene Kris
Agfa-Gevaert
Guy Joseph T.
Schilling Richard L.
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