Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Two or more radiation-sensitive layers containing other than...
Reexamination Certificate
2000-12-06
2002-07-23
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Two or more radiation-sensitive layers containing other than...
C430S506000, C430S508000, C430S509000, C430S379000
Reexamination Certificate
active
06423482
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a multilayer silver halide photographic element in which the red light sensitive record contains a relatively longer wavelength sensitized emulsion in the fastest layer and a relatively shorter wavelength sensitized emulsion in the fastest or second fastest layer.
BACKGROUND OF THE INVENTION
A typical silver halide multilayer color photographic element comprises a record sensitive to blue light, a record sensitive to green light, and a record sensitive to red light. Most often, the records are arranged so that the element is green over red, meaning that green light-sensitive record is above the red light-sensitive layer so that incident light is “seen” by the green record before the red record. Color negative elements typically have the blue sensitive layer on top, followed by the green and then the red. In order to obtain an accurate reproduction of an image, it is desirable that all three of these records accurately reproduce the colors and densities of the original subject. The red layer is normally sensitized with a dye or dyes that render the layers more sensitive at long wavelengths than the human visual system, and this can result in a failure to reproduce colors accurately.
It is desirable to have the red layer spectral sensitivity as close as possible to that of the human visual system from a pure color reproduction standpoint. If one were to attempt to identically reproduce the human eye spectral sensitivity with more short red sensitivity, another problem results. As the red spectral sensitivity is shifted to shorter and shorter wavelengths, there is a loss in red layer speed because the overlying green light sensitive layer undesirably filters out an increasing proportion of the incident light. The absorption curves of the green and red sensitive layers overlap and when the red layer is moved to ever shorter spectral sensitivities, this overlap is magnified and the filtering effect is increased. This in turn degrades the speed of the record.
Japanese published application J63/085545 discloses the possibility of sensitizing the fastest red light sensitive layer to be 3-30 nm shorter than the least sensitive red light sensitive layer in order to accurately reproduce certain shades of red. However, as indicated above, this improvement would be at the expense of speed since the shorter red sensitive fastest layer would be shadowed by the overlying green layer.
It is a problem to be solved to provide a multilayer color photographic element bearing a red light sensitive record that provides an advantageous combination of red speed and color accuracy.
SUMMARY OF THE INVENTION
The invention provides a color photographic element comprising a multilayered blue light sensitive record, a multilayered green light sensitive record, and a multilayered red light sensitive record, the red record comprising two or more layers of differing light sensitivity, the most light sensitive layer of the red record containing a red light sensitized first emulsion having at least one wavelength of peak absorption, and at least one of the two most light sensitive layers of the red record containing a red sensitized second emulsion, wherein the first emulsion exhibits, as measured at 0.2 density units above Dmin, at least one wavelength of peak absorption that is longer than the shortest wavelength of peak absorption of the second emulsion.
The invention also provides a package containing the element with prescribed development instructions or an indication of an exposure index or ISO speed of 400 or higher.
Elements of the invention are useful for providing an improved combination of speed and color rendition.
REFERENCES:
patent: 5314794 (1994-05-01), Sutton
patent: 5389506 (1995-02-01), Sutton
patent: 5817452 (1998-10-01), Kamosaki
patent: SHO 631988-85545 (1988-04-01), None
Lin Mitchell M.
Lunt Sharon R.
Sawyer John F.
Eastman Kodak Company
Kluegel Arthur E.
Letscher Geraldine
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