Color photographic silver halide material

Details Color photographic silver halide material Color photographic silver halide material

1999-10-22

2001-02-27

Letscher, Geraldine (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S503000, C430S553000, C430S557000, C430S558000, C430S569000, C430S607000, C430S608000, C430S599000, C430S604000, C430S605000

Reexamination Certificate

active

06194135

ABSTRACT:

This application is related to German Application No. 198 50 073.4 filed Oct. 30, 1998 and German Application No. 199 14 881.3 filed Apr. 1, 1999, which are incorporated by reference in its entirety for all useful purposes.
This invention relates to a negatively developing colour photographic silver halide material, at least 95 mol % of the silver halide emulsions of which consist of AgCl, and which material is distinguished on scanning exposure by elevated colour density and on analogue exposure by contrast which is independent of exposure time.
Photographic paper is used for outputting “digital prints” on scanning film recorders, in which the exposure unit exposes the image information onto the photographic material pixel by pixel, line by line with high intensity collimated light (typically from gas or diode lasers or comparable devices) and very short exposure times per pixel (in the nano- to microsecond range). During such operations, the problem of line blurring occurs, especially at elevated densities. On the image, this results in fuzzy reproduction of edges (for example of lettering) on the subject and is vividly described as “blooming”, “bleeding”, “fringe formation”, “smudging”, “fuzziness” etc. This restricts the usable density range of the photographic paper. Photographic materials for outputting “digital prints” of an elevated image quality on scanning film recorders with LEDs or lasers may thus exhibit only slight line blurring at elevated colour density (extinction).
Method for Measuring Line Blurring
A measurement method which permits the measurement of line blurring for reflective photographic material (photographic paper) is described below. This method is based on the description of the measurement of the analogous problem on a transparent photographic material (c.f. H. Frieser,
Photographischer Informationsaufzeichnung
, R. Oldenbourg Verlag, Munich (1975), pages 266 et seq.). In this method, blurring is determined on the basis of a macrodensitometric measurement. To this end, two subjects are exposed adjacent to each other with an identical stepwise intensity profile (RGB values) for the exposed structures:
1. a half-tone line screen with screen lines and spaces of the particular width b
o
[mm], which is referred to below as the “half-tone step wedge” and
2. homogeneously filled areas (“solid step wedge”).
The status A densities D
F
of the steps are determined on the solid step wedge after a defined RGB exposure. The densities D
R
of a screen line pattern exposed with these same RGB values are determined on the half-tone step wedge. According to Frieser (op. cit.), an effective (microscopic) line widening 0<&Dgr;b<b
o
may be determined on the basis of such a macrodensitometric measurement on screen line fields. This is determined by the proportions of the reflected intensity originating for each half-tone step from the screen lines themselves, i.e. T
o
, and from the spaces, i.e. T
l
(c.f. FIG.
1
).
The density of a half-tone step is calculated as follows:
D
R
=−log(T
R
)=−log(½{T
1
[1−
&Dgr;b
/b
o
]+T
o
[1+
&Dgr;b
/b
o
]})  (1)
In an ideal photographic material without blurring, &Dgr;b would be equal to 0 and consequently:
D*
R
=−log(½{T
l
+T
o
})  (2)
Thus, since 10
−Dmin
=T
l
>T
o
, the constant density 0.3+D
min
would be established asymptotically even at moderate screen line densities.
The difference between (1) and (2), the parameter D
R
−D*
R
, thus constitutes for each step the difference in density due to line blurring (c.f. FIG.
2
).
Where T
l
>T
o
, effective line widening may consequently be evaluated for each step
 &Dgr;b=b
o
(1-10
D*
R
−
D
R
)  (3)
By stepwise plotting of (3) against the density of the corresponding solid field D
F
, the usable maximum density D
F
usable
of a material may be determined directly (c.f. FIG.
3
). Tolerable line widening values according to (3) were established by visual evaluation at &Dgr;b=0.10 mm for yellow (Y), magenta (M) and cyan (C).
Performance
Exposure
Exposure was performed using a conventional film recorder (model CSI Light Jet 2080 from Cymbolic Science, Vancouver (Canada)) with the following specification according to the manufacturer's data:
Maximum
Beam diameter
Colour
Laser system
Wavelength
power
(FWHM)
Blue
argon ion
458 nm
 150 &mgr;W
25 &mgr;m
Green
helium-neon
543 nm
 80 &mgr;W
25 &mgr;m
Red
helium-neon
633 nm
2600 &mgr;W
25 &mgr;m
Paper: stationary on the inside of a half cylinder
Beam modulation: 8 bit acousto-optical modulator (AOM)
Beam mixing of blue, green and red in accordance with particular beam modulation
Beam focussing by lenses
x deflection (linewise “fast scan”): polygonal mirror rotating at 2000 rpm
y deflection (slow scan): linear displacement of polygonal mirror along the cylinder axis
Resolution 1016 dpi, exposure time per pixel: 400±100 ns
Linear dot overlap approx. 30%
The recorder was operated in linear output mode for RGB (RGB=red, green, blue), i.e. without material-specific recorder calibration (“linearisation”). The maximum exposure power for the three colour channels is reduced with regard to the different material sensitivities for yellow, magenta and cyan in such a manner that, on the one hand, the maximum density of the material may be achieved and, on the other, when an identical RGP triplet is exposed (for example RGB=(100, 100, 100)), an at least approximately neutral subject is produced (blue: 6.5 &mgr;W; green: 10.4 &mgr;W; red: 680 &mgr;W).
In accordance with the condition 0<&Dgr;b<b
o
, a b
o
of 0.25 mm was selected for the screen line test image. This corresponds to a spatial frequency of 2 line pairs/mm. The lines of the screen are written in the fast scan direction, such that the effective, device-dependent blurring corresponds to the beam diameter. Due to the resolution of 1016 dpi (=spatial frequency of 20/mm) used, this device-dependent blurring may be disregarded in comparison with the blurring intrinsic to the material.
The test subject consists of a 29 step half-tone step wedge and a solid step wedge. The subject is produced by conventional software (for example Photoshop®), exposed onto a photographic paper with the scanning film recorder and the paper is then processed using AgfaColor process 94. Step 1 receives no exposure intensity (RGB=255) and thus produces D
min
, step 29 (RGB=9) receives the maximum exposure intensity. Each pixel line was exposed in a single pass (disregarding the line overlap). Colour separations for the colours yellow, magenta and cyan and for neutral were exposed in a manner similar to that outlined for the neutral test subject by setting the complementary RGB channels to a constant 255 (without exposure). A step field is 20.0×6.35 mm in size.


REFERENCES:
patent: 4830954 (1989-05-01), Matejec
patent: 5500329 (1996-03-01), Kawai et al.
patent: 5759762 (1998-06-01), Budz et al.
patent: 0 350 046 (1990-01-01), None
patent: 0 774 689 (1997-05-01), None
patent: 1212142 (1970-11-01), None

Affiliated with

Also associated with

Rating

Color photographic silver halide material does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Color photographic silver halide material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color photographic silver halide material will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2602355