EP0093394A2 - Bildträger - Google Patents

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Publication number
EP0093394A2
EP0093394A2 EP83104120A EP83104120A EP0093394A2 EP 0093394 A2 EP0093394 A2 EP 0093394A2 EP 83104120 A EP83104120 A EP 83104120A EP 83104120 A EP83104120 A EP 83104120A EP 0093394 A2 EP0093394 A2 EP 0093394A2
Authority
EP
European Patent Office
Prior art keywords
image
layer
optical barrier
barrier layer
light scattering
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83104120A
Other languages
English (en)
French (fr)
Other versions
EP0093394A3 (de
Inventor
William T. Plummer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Polaroid Corp
Original Assignee
Polaroid Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Polaroid Corp filed Critical Polaroid Corp
Publication of EP0093394A2 publication Critical patent/EP0093394A2/de
Publication of EP0093394A3 publication Critical patent/EP0093394A3/de
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
    • G03C8/42—Structural details
    • G03C8/52—Bases or auxiliary layers; Substances therefor

Definitions

  • This invention in general relates to multilayered image carrying media and in particular to an improvement in reflection type image carrying media in which an image is viewed against a light scattering background.
  • Multilayered image carrying media in which an image formed therein is viewed against a light scattering background are known.
  • Such media are generally structured as a series of thin layers overlying one another and typically include a transparent image-receiving layer or layers in which the image is formed by an imagewise and depthwise distribution of image forming components.
  • One surface of the image-receiving layer is usually in contact with a light scattering layer against which the image is viewed through the other surface of the image-receiving layer.
  • the image is illuminated by ambient light which first passes through the viewing side of the image-receiving layer and image after which it is reflected from the light scattering layer and then in part is transmitted back through the image and image-receiving layer to the viewer.
  • FIG. 1 A well-known example of such multilayered image carrying media is the photographic color print which typically has the structure shown diagrammatically in Fig. 1.
  • the usual color print structure comprises a base of high quality white paper which carries a baryta layer.
  • the baryta largely barium sulfate powder suspended in gelatin, operates as an efficient diffuse reflector.
  • the image forming layers are coated on the baryta and typically comprise either three separate layers containing cyan, magenta, and yellow dye components or, in the case of imbibition processes, a single dyeable gelatin layer which takes up all three image dyes.
  • Color prints thus structured can be thought of as color transparencies in optical contact with a diffuse white reflector.
  • This feature relates to the proximity of the image receiving layer to the light scattering layer or pigment as the case may be. With a separation of only a few wavelengths of visible light between the pigment scattering grains and the ultimate location of the image dyes, these dyes can become unwelcome participants in the multiple rescattering of light between pigment grains. Without the extreme proximity, all light held in the pigment layer by total reflection at the pigment boundary would be free of dye absorption: only light leaving the pigment and penetrating the entire thickness of the dye receiving layer or layers is affected by the dyes. But in cases where the dyes are very close to the pigment layer, a new consideration is introduced which, it is believed, has not heretofore been recognized and which makes the multiple internal reflection problem more severe as will subsequently be described in the detailed disclosure.
  • the invention accordingly comprises the products possessing the construction, combination and arrangement of elements exemplified in the following detailed disclosure and methods or processes inherent in their use.
  • the present invention relates to the provision of an optical barrier layer in reflection type multilayered image carrying media, such as photographic color prints, for purposes of minimizing the effects of multiple internal reflections in cases where the image forming components, which may be dyes, are at or nearly at the interface between a transparent image-receiving layer and a light scattering layer against which the image is viewed by ambient light reflected from the light scattering layer.
  • the problem it solves will first be illustrated by considering the simple multilayered image carrying medium shown in Fig. 2 and designated at 10.
  • the structure of the medium 10 is quite general from an optical point of view, it being understood that the various layers shown may be provided in a variety of well-known ways through the use of appropriate chemicals and associated processes.
  • the image medium 10 can be seen to comprise an image receiving layer 12 having an index of refraction, n, and including therein an image formed of dyes arranged in a thin layer at or nearly at the interface between the image receiving layer and a light scattering layer 14 which may be formed, for example, of Ti0 2 pigments.
  • the light scattering layer 14 has an index of refraction, m, and diffusely reflects ambient light which illuminates the image for viewing purposes.
  • the pigment in the light scattering layer 14 can be considered a thorough isotropic scatterer of light so that the layer 14 can be considered a Lambert reflector, and light within the pigment layer 14 is rescattered from grain to grain many times after which it emerges.
  • the emergent light may be in one of three forms:
  • a Lambert diffuse reflector has a remarkable property: it remains a Lambert reflector as it is immersed in a succession of transparent layers, despite the action of Snell's law. This happens because "the differential form of Snell's law is the ratio of the cosines of the internal and external angles.
  • the regions I, II, and III correspond to the three kinds of emergent light. Since the pigment layer 14 is a thorough isotropic scatter of light, an observer immersed in the clear layer 12 would see the same brightness emitted by the surface at all angles, so the amount of light passed by a unit area of the pigment surface in any one direction would be weighted by the Lambert foreshortening cosine.
  • the total light budget upon "leaving" the pigment is:
  • the receiving layer is distributed at 100 mg/ft. 2 , it would have a thickness of 1.08 micron for a specific gravity of 1. For a specific gravity of about 1.2 it would be 0.9 micron, or 1.6 vacuum wavelengths, or 2.5 wavelengths in this material, or 3.9 wavelengths of light in the high-index pigment.
  • the most effective correction for this problem is to incorporate a clear, preferably dye-permeable, chemically inert, optical barrier layer (16) between the pigment and the dye receiving layer as shown in Fig. 3. Any thickness is helpful, and most of the benefit should be achieved at 30 to 50 mg/ft. 2 . A low index is most advantageous, but even an index of 1.5 or 1.6 would relieve the attenuated total reflection problem.
  • An example of a material suitable for such a layer would be gelatin, cross-linked polyacrylamide, or hydroethylcellulose. A few wavelengths thick or more is preferred but even a thickness of 0.5 micrometers would work. It is believed that no previous consideration has been given to this problem, nor has the optical barrier as a solution to it been proposed.
  • n is the index of the image receiving layer 12 and R is the apparent diffuse reflectivity (0° and 45°) geometry of the print when t is the one way transmission through the image-receiving layer 12.
  • w .80/(9 - 39°)
  • the integrals may now be carried out numerically for any desired combination of t and B.
  • the values of t simply trace out the range of densities to be investigated, and B may be thought of as a coupling coefficient, controlled by how localized the dye may be in the bottom part of the receiving layer 12 as shown in Fig. 4 wherein the abcissa represents the amount of dye needed to achieve the density, D t , against a 100% reflecting mirror. For any given t, more localized dye will correspond to higher B.
  • the new contribution can have an enormous effect on maximum density when 0 is large.
  • the effect on the film characteristic curve is to raise the higher density somewhat and steepen the slope.
  • This effect is strongly wavelength- dependent through the effective thickness, w, so density is increased more for red light than for blue.
  • the addition of 30 to 50 mg/ft. 2 of barrier layer should lower the red maximum density substantially, the green somewhat less, and the blue least of all.
  • This barrier layer may also reduce color changes as a print matures, and may reduce any color irregularity being introduced by differences in dye location within the image-receiving layer.
  • the attenuated total reflection concern is less if the pigments have lower index (such as baryta), and may be entirely negligible if the image-receiving layer 12 is very much thicker than the penetration depth of light reflected at the pigment-image-receiving layer boundary.
  • the optical barrier layer of the present invention may be incorporated in a variety of multi- layered film structures in which image forming components are located within a few wavelengths of a light scattering layer against which the image is viewed for purposes of reducing the effects of multiple internal reflections.
  • the optical barrier layer may be incorporated in self-processable film into structures of the type described in U.S. Patent No. 3,415,644 issued on December 10, 1968 to Edwin H. Land.
  • photographic products and processes are described in which a photosensitive element and an image-receiving element are maintained in fixed relationship prior to exposure, and this relationship is maintained after processing and image formation.
  • the final image is viewed through a transparent (support) element against a reflection, i.e., white background.
  • Photoexposure is made through the transparent element and application of a processing composition provides a layer of light-reflecting material to provide a white background for viewing the final image through the transparent support.
  • the light-reflecting material is preferably titanium dioxide which inter alia provides an opacifying function. If the image forming components in such film unit structures were located in the image-receiving layer within a few wavelengths of the titanium dioxide reflecting layer, multiple internal reflection effects could be significant for the reasons discussed above and would be minimized by placing the optical barrier layer of the invention between the image-receiving layer and the titanium dioxide background.
  • the optical barrier layer (16) is preferably chemically inert and permeable with respect to dyes which need to diffuse therethrough to form the image, but impermeable with respect to the pigments included in the light scattering layer.
  • the materials mentioned hereinbefore have these characteristics and may be applied as layers in well-known manners.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Architecture (AREA)
  • Structural Engineering (AREA)
  • Thermal Transfer Or Thermal Recording In General (AREA)
  • Laminated Bodies (AREA)
EP83104120A 1982-04-28 1983-04-27 Bildträger Withdrawn EP0093394A3 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US37261882A 1982-04-28 1982-04-28
US372618 1982-04-28
US48028783A 1983-03-30 1983-03-30
US480287 1995-06-07

Publications (2)

Publication Number Publication Date
EP0093394A2 true EP0093394A2 (de) 1983-11-09
EP0093394A3 EP0093394A3 (de) 1984-10-03

Family

ID=27005838

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83104120A Withdrawn EP0093394A3 (de) 1982-04-28 1983-04-27 Bildträger

Country Status (2)

Country Link
EP (1) EP0093394A3 (de)
CA (1) CA1247912A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0531839A1 (de) * 1991-09-11 1993-03-17 Polaroid Corporation Aufzeichnungsmittel mit Schicht mit niedrigem Brechungsindex

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD71936A (de) *
US2391127A (en) * 1942-02-17 1945-12-18 Eastman Kodak Co Antihalation coatings
FR944375A (fr) * 1946-03-15 1949-04-04 Kodak Pathe Perfectionnements aux films antihalo
US4167414A (en) * 1978-09-28 1979-09-11 E. I. Dupont De Nemours And Company Reflective opaque polyester film base support for inverse transfer negative emulsions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD71936A (de) *
US2391127A (en) * 1942-02-17 1945-12-18 Eastman Kodak Co Antihalation coatings
FR944375A (fr) * 1946-03-15 1949-04-04 Kodak Pathe Perfectionnements aux films antihalo
US4167414A (en) * 1978-09-28 1979-09-11 E. I. Dupont De Nemours And Company Reflective opaque polyester film base support for inverse transfer negative emulsions

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0531839A1 (de) * 1991-09-11 1993-03-17 Polaroid Corporation Aufzeichnungsmittel mit Schicht mit niedrigem Brechungsindex

Also Published As

Publication number Publication date
EP0093394A3 (de) 1984-10-03
CA1247912A (en) 1989-01-03

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Inventor name: PLUMMER, WILLIAM T.