Apparatus for controlling the color balance of a photographic image

• US 4,918,470 A
• Filed: 12/05/1988
• Issued: 04/17/1990
• Est. Priority Date: 12/05/1988
• Status: Expired due to Term

• Current Assignee: Senshin Capital LLC (Intellectual Ventures LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Whiteside, George D.
• Primary Examiner(s): Adams, Russell E.
• Application Number:
  US07/279,659
• Time in Patent Office: 498 Days
• Field of Search: 354/482, 354/430, 354/21
• US Class Current: 396/209
• CPC Class Codes: G03B 7/095 for control of aperture
• CPC Class Codes: G03B 7/18 in accordance with light-reducing "factor" of filter or other obturator used with or on the lens of the camera
• CPC Class Codes: G03B 7/24 automatically in accordance with markings or other means indicating film speed or kind of film on the magazine to be inserted in the camera

Abstract

A selected one of two or more variable density color filters is automatically positioned in the optical axis of a taking lens of a photographic camera, if necessary, prior to an exposure in order to automatically effect a color balanced exposure of a photosensitive material located within the camera. The color balance of a photographic image formed in a photosensitive material is dependent upon several factors. These factors include the color balance of the photosensitive material, the color temperature of scene illumination and the temperature of the photosensitive material processing fluid. In the present arrangement, the position of the variable density filter in the optical path of the taking lens is concurrently dependent upon one or more of these factors which, under certain conditions, may collectively offset one another such that movement of a variable density color filter for photographic image color balancing purposes does not occur.

Claims

1. Photographic apparatus comprising:

a film cassette for containing at least one frame of a photosensitive material and having indicia on an external surface thereof in which a characteristic of the photosensitive material is encoded in a binary format;

means for supporting the photosensitive material in position for exposure;

means for directing scene light along an optical path and onto the photosensitive material during an exposure;

an optical filter assembly having at least one filter, said optical filter assembly having a first mode of operation wherein one filter is positioned within said optical path and filters the scene light before it strikes the photosensitive material, and a second mode of operation wherein said one filter is located out of the optical path and scene light is permitted to strike the photosensitive material in an unfiltered condition;

means responsive to an encoded photosensitive material characteristic in said indicia and to a factor external of the photosensitive material for generating a composite signal representative of the extent such characteristic and factor may have on the color balance of a photographic image subsequently formed in such photographic material; and

means coupled to said optical filter assembly and responsive to said composite signal for placing said optical filter assembly in either said first or second modes of operation in accordance with said signal, prior to the exposure of the photosensitive material.

2. The photographic apparatus of claim 1 wherein said optical filter assembly includes a filter carrier for rotatably supporting a pair of variable density optical filters, each of a different color, that are separated from each other by an aperture, said placing means is coupled to said filter carrier and said placing means positions one of said filters or said aperture in said scene light path in response to said color balance signal.

3. The photographic apparatus of claim 2 wherein each of said variable density filters are of a wedge shape that linearly varies from a minimum density to a maximum density with the minimum density of said filter being adjacent said aperture and the maximum density of said filter being remote therefrom.

4. The photographic apparatus of claim 3 wherein one of said variable density filters is blue and the other of said variable density filters is yellow.

5. The photographic apparatus of claim 1 wherein said optical filter assembly includes three filter carriers with each carrier rotatably supporting a different color variable density optical filter, said placing means is selectively coupled to each of said filter carriers and said placing means positions one of said filters in said scene light path in response to said color balance signal.

6. The photographic apparatus of claim 5 wherein each of said variable density filters are of a wedge shape that linearly varies from a minimum density light filtering portion to a maximum density light filtering portion with the minimum density portion of each of said filters entering said scene light path before said maximum density portion when positioned into the scene light path in response to said color balance signal for light filtering purposes.

7. The photographic apparatus of claim 6 wherein one of said variable density filters is cyan, one of said variable density filters is magenta and the remaining variable density filter is yellow.

8. Photographic apparatus comprising:

a film cassette for containing at least one frame of a photosensitive material and having indicia on an external surface thereof in which the color balance of the photosensitive material is encoded in a binary format;

means for locating the film cassette in position for the subsequent exposure of the photosensitive material;

means for directing scene light along an optical path and onto the photosensitive material during an exposure cycle;

an optical filter assembly having at least one filter, said optical filter assembly having a first mode of operation wherein said one filter is positioned within said optical path and filters the scene light before it strikes the photosensitive material, and a second mode of operation wherein said one filter is located out of the optical path and scene light is permitted to strike the photosensitive material in an unfiltered condition;

means responsive to the color temperature of a scene to be photographed and to the color balance of the photosensitive material encoded in said indicia for generating a composite signal representative thereof; and

means coupled to said optical filter assembly and responsive to said composite signal for placing said optical filter assembly in either said first or second modes of operation in accordance with said composite signal, prior to the commencement of an exposure of the photosensitive material.

9. Photographic apparatus for use with a film cassette containing at least one self-developing film unit having a layer of photosensitive material and a quantity of processing liquid enclosed in a portion thereof, comprising:

means for locating the film cassette in position for the subsequent exposure of the photosensitive material;

means for directing scene light along an optical path and onto the photosensitive material during an exposure cycle;

means for spreading the processing liquid across a layer of the film unit subsequent to its exposure to the scene light so as to initiate the formation of a visible image within the film unit;

a chamber formed within said photographic apparatus for temporarily receiving the film unit after said spreading of the processing liquid across the layer of the film unit;

an optical filter assembly having at least one filter, said optical filter assembly having a first mode of operation wherein said one filter is positioned within said optical path and filters the scene light before it strikes the photosensitive material, and a second mode of operation wherein said one filter is located out of the optical path and scene light is permitted to strike the photosensitive material in an unfiltered condition;

means responsive to the temperature in said chamber and to the color balance of the photosensitive material for generating a composite signal representative thereof; and

means coupled to said optical filter assembly and responsive to said composite signal for placing said optical filter assembly in either said first or second modes of operation in accordance with said composite signal prior to the commencement of an exposure of the photosensitive material.

10. Photographic apparatus for use with a film cassette containing at least one frame of a photosensitive material of the self-developing type including a quantity of processing liquid enclosed in a portion thereof, comprising:

means for locating the film cassette in position for the subsequent exposure of the photosensitive material;

means for directing scene light along an optical path and onto the photosensitive material during an exposure cycle;

means for spreading the processing liquid across a layer of the film unit after exposure to the scene light;

a chamber formed within said photographic apparatus for temporarily receiving the frame of photosensitive material after said spreading;

an optical filter assembly having at least one filter, said optical filter assembly having a first mode of operation wherein said one filter is positioned within said optical path and filters the scene light before it strikes the photosensitive material, and a second mode of operation wherein said one filter is located out of the optical path and scene light is permitted to strike the photosensitive material in an unfiltered condition;

means responsive to the temperature in said chamber and to the color temperature of the scene to be photographed for generating a composite signal representative thereof; and

means coupled to said optical filter assembly and responsive to said composite signal for placing said optical filter assembly in either said first or second modes of operation in accordance with said composite signal, prior to the commencement of an exposure of the photosensitive material.

11. Photographic apparatus for use with a film cassette containing at least one frame of a photosensitive material of the self-developing type including a quantity of processing liquid enclosed in a portion thereof, comprising:

means for locating the film cassette in position for the subsequent exposure of the photosensitive material;

means for directing scene light along a path and onto the photosensitive material during an exposure cycle;

means for spreading the processing liquid across a layer of the film unit after exposure to the scene light;

a chamber formed within said photographic apparatus for temporarily receiving the frame of photosensitive material after exposure to the scene light and after said spreading means has spread the processing liquid;

an optical filter assembly having at least one filter, said optical filter assembly having a first mode of operation wherein said one filter is positioned within said optical path and filters the scene light before it strikes the photosensitive material, and a second mode of operation wherein said one filter is located out of the optical path and scene light is permitted to strike the photosensitive material in an unfiltered condition;

means responsive to the temperature in said chamber, the color temperature of the scene to be photographed and to the color balance of the photosensitive material for generating a composite signal representative thereof; and

means coupled to said optical filter assembly and reponsive to said composite signal for placing said optical filter assembly in either said first or second modes of operation in accordance with said composite signal, prior to the commencement of an exposure of the photosensitive material.

12. The photographic apparatus of claim 11 wherein the film cassette has indicia thereon representative of the color balance of photosensitive material contained therein and said composite signal is derived, in part, in response to the indicia on the film cassette.

13. The photographic apparatus of claim 12 wherein the indicia comprises a plurality of adjacent electrically conductive and electrically non-conductive areas on an external surface of the film cassette with the collective conductivity and non-conductivity of the surface areas being representative of the color balance of the photosensitive material contained within the film cassette.

14. The photographic apparatus of claim 11 wherein the film cassette has indicia thereon representative of the date of manufacture of the photosensitive material contained therein, said apparatus further includes means responsive to the date of manufacture indicia for generating a signal representative thereof, and said placing means is additionally responsive to said date of manufacture signal.