Color photographic element containing three silver halide layers sensitive to infrared

Full color photographic images are produced by exposure of a radiation-sensitive element comprising at least three silver halide emulsion layers. At least two silver halide emulsion layers are sensitized to infrared radiation. Selectively absorptive filter layers and/or differential sensitivities between emulsion layers are used to prevent exposure of other layers to radiation used to expose a single layer.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to color photographic elements and in particular to 
color photographic elements capable of providing full color images with 
exposure of at least two silver halide emulsion layers to radiation 
outside the visible region of the electromagnetic spectrum. In particular, 
the present invention relates to a color photographic element having at 
least three emulsion layers associated with color image providing 
materials, each emulsion layer being sensitized to a different region of 
the electromagnetic spectrum and at least two layers being sensitized to 
radiation within the infrared region of the electromagnetic spectrum. 
2. Background Art 
Dyes which have been capable of sensitizing silver halide emulsions to 
infrared regions of the electromagnetic spectrum have been known for many 
years. Merocyanine dyes and cyanine dyes, particularly those with longer 
bridging groups between cyclic moieties have been used for many years to 
sensitize silver halide to the infrared. U.S. Pat. Nos. 3,619,154, 
3,682,630; 2,895,955; 3,482,978; 3,758,461 and 2,734,900; and U.K. Patent 
Nos. 1,192,234 and 1,188,784 disclose well-known classes of dyes which 
sensitize silver halide to portions of the infrared region of the 
electromagnetic spectrum. U.S. Pat. No. 4,362,800 discloses dyes used to 
sensitize inorganic photoconductors to the infrared, and these dyes are 
also effective sensitizers for silver halide. 
With the advent of lasers, and particularly solid state laser diodes 
emitting in the infrared region of the electromagnetic spectrum (e.g., 780 
to 1500 nm), the interest in infrared sensitization has greatly increased. 
Many different processes and articles useful with laser diodes have been 
proposed. U.S. Pat. No. 4,416,522, for example, proposes daylight 
photoplotting apparatus for the infrared exposure of film. This patent 
also generally proposes a film comprising three emulsion layers sensitized 
to different portions of non-visible portions of the electromagnetic 
spectrum, including the infrared. The film description is quite general 
and the concentration of imagewise exposure on each layer appears to be 
dependent upon filtering of radiation by the apparatus prior to its 
striking the film surface. 
BRIEF DESCRIPTION OF THE INVENTION 
A photographic element is described which is capable of providing full 
color images without exposure to corresponding visible radiation. The 
element comprises at least three silver halide emulsion layers on a 
substrate. The at least three emulsion layers are each associated with 
different photographic color image forming materials, such as color 
couplers capable of forming dyes of different colors upon reaction with an 
oxidized color photographic developer, diffusing dyes, bleachable dyes, or 
oxidizable leuco dyes. The three emulsion layers are sensitized to three 
different portions of the electromagnetic spectrum with at least two 
layers sensitized to different regions of the infrared region of the 
electromagnetic spectrum. The layers must be in a construction that 
prevents or reduces the exposure of layers by radiation intended to expose 
only one other layer. This is done by providing differences in speed of 
emulsions sensitive to different wavelengths of the infrared.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1A shows the D vs logE curve for the photographic element of Example 1 
when exposed to 780 nm radiation. Curve (a) shows the density of the 
yellow-forming layer which is sensitized to 780 nm. Curve (b) shows the 
density of the magenta-forming layer which is sensitized to 830 nm. Curve 
(c) shows the density of the cyan-forming layer which is sensitized to 880 
nm. 
Secondary absorption is observed in the low density regions (0.1 to 0.5) of 
the cyan and magenta color D logE curves. These unwanted low density bumps 
are due to residual green absorption characteristics of the yellow dye or 
the residual red absorption characteristics of the magenta dye and are 
read with the green or red filters of the densitometer. The same secondary 
absorption in the cyan curve of FIG. 1B is also observed. Subtraction of 
these unwanted color-related absorptions from the actual exposure curves 
would yield adequate separation. 
FIG. 1B shows the D vs logE curve for the photographic element of Example 1 
when exposed to 830 nm radiation. Curve (b) shows the magenta-forming 
layer and Curve (c) shows the cyan-forming layer. 
FIG. 1C shows the D vs logE curve for the photographic element of Example 1 
when exposed to 890 nm radiation. Curve (c) shows the cyan-forming layer. 
FIG. 2 shows the D vs logE curve for the photographic element of Example 2 
when exposed to 780 nm radiation. Curve A shows the yellow-forming layer. 
Curve B shows the magenta-forming layer in the element without a filter 
layer. Curve B' shows the magenta-forming layer when a filter dye is 
present between layers 3 and 5. Curve C shows the cyan-forming layer. The 
shift in the D vs logE curve between Curves B and B' is 0.38 Log E units. 
DETAILED DESCRIPTION OF THE INVENTION 
A photographic element is herein described which photographic element is 
capable of providing a full color image or three color images with 
exposure of at least two silver halide emulsion layers to radiation 
outside the visible region of the electromagnetic spectrum comprising: 
(a) a substrate, and 
(b) on one side of said substrate at least three silver halide emulsion 
layers, each of said silver halide emulsion layers being associated with a 
means for forming a single color image of a different color dye, 
said three silver halide emulsion layers comprising in any order a first 
emulsion sensitized to a first portion of the infrared region of the 
electromagnetic spectrum, a second silver halide emulsion sensitized to a 
second portion of the infrared region of the electromagnetic spectrum, the 
wavelength of maximum spectral sensitivity of which second emulsion 
differs by at least 15 nm from the wavelength of maximum spectral 
sensitivity to which said first emulsion is sensitized, and a third silver 
halide emulsion sensitized to a third portion of the electromagnetic 
spectrum the wavelength of maximum spectral sensitivity of which portion 
differs by at least 15 nm from each of the wavelengths of maximum 
sensitivity to which said first and second emulsions are sensitized, the 
sensitivities of each of said three emulsion layers being such that 
between any two emulsion layers which are sensitized to portions of the 
infrared region of the electromagnetic spectrum, the emulsion having a 
wavelength of maximum spectral sensitivity which is the shorter of said 
two infrared sensitive layers has a speed at the wavelength of its maximum 
spectral sensitivity which is at least 0.2 logE units faster than the 
other of said two infrared sensitive layers. It has been found that with a 
difference in the wavelengths of at least 15 nm, the use of sensitivity 
differences alone at the wavelengths of maximum spectral sensitivity for 
each of the layers can provide color separation in the final image. This 
is particularly surprising because dyes which sensitize to the infrared, 
even those dyes capable of J-banding, tend to have long ranges of 
absorbance and hence sensitivity. For example, when a dye is chosen to 
sensitize an emulsion at 850 nm, it will also tend to sensitize with 
essentially equal effectiveness across the entire range of at least 
800-850 nm. Thus, if two identical emulsions in the same photographic 
elements were sensitized with dyes having maximum spectral wavelengths of 
sensitivity at 800 nm and 850 nm, respectively, exposure to radiation of 
800 nm would tend to equally expose both emulsions, thereby producing 
essentially no color separation. 
Because of the small decrease in sensitivity effected by often large (e.g., 
50 nm) movements towards shorter wavelengths within the regions of the 
electro-magnetic spectrum in which an infrared sensitizing dye will 
effectively sensitize, at least the 15 nm difference in the wavelengths of 
maximum spectral sensitivity desired. It is preferred that the difference 
between any two layers sensitive to the infrared be at least 20 nm, more 
preferred that the difference be at least 35 nm, and most preferred that 
the difference in wavelengths of maximum spectral sensitivity be at least 
50 nm between any two layers sensitized to the infrared. The closer the 
wavelengths of maximum spectral sensitivity between layers, the greater 
should be the difference in sensitivities and the higher the contrasts. 
The use of filter layers between emulsion layers can help reduce the 
needed levels of sensitivity differences between layers. By using a filter 
dye between layers which absorbs strongly at the wavelengths of maximum 
spectral sensitivity of the uppermost emulsion layer (with respect to the 
direction from which exposure occurs), the needed difference in 
sensitivity of the lower layer can be somewhat reduced. 
The preferred arrangement of layers has the wavelengths of maximum spectral 
sensitivity in the respective layers getting longer as one moves away from 
the direction (or surface) from which the exposure is to be made. That is, 
using for example, color paper or print as a reference, the infrared 
sensitive layer furthest from the paper base has a wavelength of maximum 
spectral sensitivity which is shorter than the wavelength of maximum 
spectral sensitivity of any other emulsion layer closer to the base. This 
preference is because sensitization peaks of dyes tend to fall off more 
quickly towards longer wavelengths making sensitivity separation more 
easily effected and filter dyes more easily chosen. 
As previously described, when all three emulsion layers are within the 
infrared region of the electromagnetic spectrum, any two layers must have 
wavelengths of maximum spectral sensitivity differing by at least 15 mm 
and speed differences of at least 0.2 logE units. When two layers are 
sensitive to wavelengths within the infrared and the third is sensitized 
to a wavelength in the visible, such differential speed considerations 
should not be necessary with a reasonable selection of the wavelength of 
maximum sensitization. Spectral sensitizing dyes are available across the 
entire visible spectrum and even in to the ultraviolet. One of ordinary 
skill in the art could thus easily sensitize the third emulsion layer to a 
wavelength outside the infrared where there would be practically no 
overlap in spectral sensitization effected by the various sensitizing 
dyes. For example, the third emulsion layer could be sensitized more than 
100 nm below the infrared (beginning approximately at about 750-780 nm) to 
the blue, green or yellow portions of the electromagnetic spectrum. If for 
any reason it were desired to have the third emulsion layer sensitized to 
a portion of the spectrum less than 100 nm from the shortest wavelength 
within the infrared to which an emulsion is sensitized, it would be 
desirable to give consideration to adjusting the speed of the emulsion 
sensitized to the visible in a manner similar to that done for shorter 
wavelengths within the infrared. If the emulsion layer sensitized to the 
visible portion of the electromagnetic spectrum is near to the infrared 
(e.g., within 50 nm of the shortest wavelength within the infrared to 
which an emulsion of the element has been spectrally sensitized), the 
speed of the emulsion sensitized to the visible should also be at least 
0.2 or at least 0.5 logE units faster than the speed of the emulsion 
sensitized to a wavelength within the infrared nearest the visible portion 
of the spectrum. The use of spectral sensitizing dyes within the visible 
portion of the electromagnetic spectrum which form J-bands will 
effectively reduce the impact of this consideration. There should also be 
a difference of at least 15 nm between the wavelengths of maximum spectral 
sensitivity for layers within and without the infrared. 
The speed of the emulsion layers is to be determined, at all times, at the 
wavelength of maximum spectral sensitivity for the emulsion layer. The 
term wavelength of maximum sensitivity should be read as wavelength of 
maximum spectral sensitivity in the practice of the present invention, 
that is, the wavelength of maximum sensitivity effected by the addition of 
spectral sensitizing dyes. 
The broadest range of contrasts for use in construction of emulsions within 
the present invention is about 0.5 to 12. The lower limit is essentially a 
function of the power available from lasers in imaging apparatus. The 
upper limit tends to be a function of the type of use to which the film or 
paper is to be used. A range of 1 to 11 for contrast is preferred; a 
contrast of 2 to 8 is more preferred. 
A photographic element is further herein described, which photographic 
element is capable of providing a full color image with exposure of at 
least two silver halide emulsion layers to radiation outside the visible 
region of the electromagnetic spectrum comprising 
(a) a substrate, and 
(b) on one side of said substrate at least three silver halide emulsion 
layers, each of said silver halide emulsion layers being associated with a 
means for forming a single color image of a different color dye, 
said three silver halide emulsion layers comprising a first emulsion 
sensitized to a portion of the infrared region of the electromagnetic 
spectrum, a second emulsion sensitized to a portion of the infrared region 
of the electromagnetic spectrum which is of a shorter wavelength than the 
portion to which said first emulsion is sensitized, and a third emulsion 
sensitized to a portion of the electromagnetic spectrum which is of a 
shorter wavelength than that portion to which said second emulsion is 
sensitized, and said three silver halide emulsion layers having a 
construction selected from the group consisting of: 
(1) each of the three layers having a contrast between 0.5 and 12, 
preferably between 1 and 11, most preferably between 2 and 8, differing 
from each other in photographic speed such that, at an optical density of 
1.3, the speed of the third emulsion (when sensitized to the infrared) is 
at least 0.2 logE units faster than the second emulsion layer, and the 
second emulsion is at least 0.2 logE units faster than the first emulsion 
layer, 
(2) between said first and second emulsion layers is a filter layer 
absorbing infrared radiation in a range overlapping the region of maximum 
sensitivity of said second emulsion layer without absorbing more than 
forty percent of the infrared radiation to which said first emulsion layer 
is sensitized, and when said third layer is also sensitized to the 
infrared region of the spectrum, between said second emulsion layer and 
said third emulsion layer is a filter layer absorbing radiation in a range 
overlapping the region of maximum sensitivity of said third emulsion layer 
without absorbing more than forty percent of the infrared radiation to 
which second layer is sensitized, and 
(3) directly between two layers comprising either said first and second 
emulsion layers or said second and third emulsion layers, when said third 
layer is also sensitized to the infrared region of the spectrum, a filter 
layer absorbing radiation in a range overlapping the region of maximum 
sensitivity of the one of the two layers farther away from the substrate 
without absorbing more than forty percent of the infrared radiation to 
which the other of said two layers is sensitized and the other pair of 
emulsion layers comprising said second and third emulsion layers and said 
first and second emulsion layers, respectively, having a contrast between 
0.5 and 12, preferably between 1 and 11, most preferably between 2 and 8 
and differing in speed from each other so that at an optical density of 
1.3, the speed of the emulsion layer farthest from the substrate in said 
other pair of emulsion layers is at least 0.2 logE units faster than the 
speed of the emulsion layer closest to the substrate in said other pair of 
emulsion layers. 
The higher the contrast in the emulsion layers in the practice of the 
present invention, the smaller need be the differences in speed. For 
example, with a contrast of 8 for the emulsion layers, a speed difference 
of 0.2 logE units at their wavelengths of maximum sensitivity would be 
sufficient. Below about 4.5 in contrast, the difference in speed must 
usually be at least 0.4 logE units, and with a contrast between about 2 
and 4, the speed difference must usually be at least 0.5 logE units. 
The relative order in the relationship of the emulsion layers of the 
present invention is important in obtaining benefits from the technology. 
The first layer, as described above, must be the emulsion layer farthest 
from the imaging radiation. Thus, where exposure would be through a 
transparent base, the first layer would be the emulsion layer farthest 
from the base, the top emulsion layer from a conventional perspective. 
Normally, photographic elements are not exposed through the base, and the 
first layer would normally be the infrared sensitized emulsion layer 
closest to the base. 
As noted above, it is preferred that all of the silver halide emulsion 
layers are sensitized to different infrared regions of the electromagnetic 
spectrum. It is essential that at least two layers be sensitized to 
different infrared regions of the electromagnetic spectrum. The order of 
those at least two layers must still be that the emulsion layer sensitized 
to the longer wavelength is closest to the side of the photographic 
element first struck by the exposing radiation. There is more flexibility 
with respect to the placement of other silver halide emulsion layers which 
are sensitized to visible portions of the electromagnetic spectrum. For 
example, if a system were to be made which is composed of three emulsion 
layers sensitized to 800 nm and 880 nm and 580 nm (yellow), filter layers 
and reduced sensitivity of the emulsion layers would not be essential 
between the yellow layer and either of the infrared sensitive layers. The 
differential in sensitivity and/or filter layers would still have to exist 
between any two infrared sensitive layers. If the element were constructed 
with the emulsion layers (as counted towards the base) sensitized to 
(1) 580 nm, 
(2) 800 nm, and 
(3) 880 nm, the filter layer (if any), would have to be placed between 
layers 
(2) and 
(3) or the emulsion sensitivities must differ, as required in the practice 
of the present invention, only as between layers 
(2) and 
(3). Layer 
(1) would merely be constructed as a conventional yellow forming silver 
halide emulsion layer (or negative dye forming layer). If the yellow layer 
were placed in a construction between the two infrared sensitized layers, 
such as 
(1) 800 nm, 
(2) 580 nm, and 
(3) 880 nm, any filter layers must be between layers 
(1) and 
(3) and could be placed between layers 
(1) and 
(2) or between layers 
(2) and 
(3). The difference in emulsion sensitivity, if used, according to the 
practice of the present invention would be between layers 
(1) and 
(3). The sensitivity of layer 
(2) would be selected only on the basis of the activity desired to produce 
an effective yellow color. There are no significant considerations of 
guarding against exposure of layer 2 by radiation used to expose layers 
(1) or 
(3). Filters could be used if the dyes in layer 
(2) had a long tail on its absorption curve, but that would occur only with 
less than skillful selection of the yellow sensitizing dye. 
If the visible light sensitive emulsion layer is used as the emulsion layer 
farthest from the base, similar considerations must be made. The filter 
layer would still have to be between the two infrared sensitive layers, if 
a filter layer is used. The difference in emulsion sensitivity must also 
be present between the two infrared sensitized layers if that method, 
according to the teachings of the present invention, is used. 
The infrared portion of the electromagnetic spectrum is given various 
ranges, but is generally considered to be between 750 to 1500 nm which 
overlaps a small portion of the visible regions of the electromagnetic 
spectrum (e.g., about 750-780 nm). A large number of dyes are known to 
sensitize silver halide emulsions to various portions of the infrared 
region of the spectrum. In particular, cyanines and merocyanines are well 
documented as infrared sensitizers for various types of imaging systems 
including silver halide emulsions. For example, U.S. Pat. Nos. 2,104,064; 
2,734,900; 2,895,955; 3,128,179; 3,619,154; 3,682,630; and 4,362,800 
disclose many dyes which are sensitizers to the infrared. Photographic 
Chemistry, Vol. 2, P. Glafkides, 1960, Fountain Press, Chapter XL, pages 
882-901 describes the spectral sensitization of silver halide emulsions to 
the infrared as does, more generally, The Theory of the Photographic 
Process, 3rd Ed., Mees and James, 1966, Chapter II, esp. pp. 199 and 205. 
The following formulae represent examples of known infrared sensitizing 
dyes. These dyes are described in Mees and James, supra; Glafkides, supra; 
and U.S. Pat. No. 2,895,955. 
In order that each emulsion is sensitized to respond to specific regions of 
the infrared spectrum, the sensitizing dyes chosen are extremely important 
to the construction of the color multilayer material. As shown in the 
following formulae, these dye structures are usually symmetrical or 
unsymmetrically substituted dicarbocyanines 1 and tricarbocyanines 2 with 
the auxochromic portions of the dyes being lepidine 3, quinoline 4, 
naphthothiazole 5, benzothiazole 6, and so forth. Heterocyclics may also 
be introduced into the methine chain to increase rigidity and stability of 
the dye molecule. 
Some typical IR-sensitizing dyes 7-9 are shown in the following formulae. 
Each of these dyes was added to a silver chlorobromide emulsion coated and 
subsequently were exposed at various times with the emission from a 
tungsten-lamp source on a wedge spectrograph. The characteristic shape of 
their curves is a broad tail of sensitization stretching 150 to 300 nm 
from the peak of maximum sensitization to the shorter wavelength side of 
the spectrum, but a narrow tail of sensitization approximately 50 to 70 nm 
wide on the longer wavelength side. Other cyanine-type dyes 10-20 with 
various auxochromic end groups also exhibited similar sensitization curves 
on the emulsion. The wavelength of the peak of maximum sensitization 
(Peak) and the wavelength of the point at which minimum sensitization at 
longer wavelengths occur (Minimum) are shown. Any of the known useful 
anions may be associated with these compounds, but I.sup.-, Br.sup.-, 
tosylate, and para-toluene sulfonate are preferred. 
These infrared sensitizing dyes, like most other sensitizing dyes do not 
have monochromatic absorption curves, but absorb, and thus sensitize to, a 
range of radiation wavelengths. Even J-banding dyes, which tend to have a 
narrower range of absorption for each dye, absorb over a range of the 
electromagnetic spectrum. This range can extend from a few nanometers up 
to a few hundred nanometers. Even though exposing radiation sources from 
lasers can be essentially monochromatic, the spectral sensitivities of 
even single layer emulsions may have maximum sensitivities at the 
wavelength of the exposing radiation, but still bracket that wavelength 
with a range of sensitivity. 
State of the art infrared laser diodes tend to emit radiation between 
wavelengths of 750-950 nm. This tends to be too narrow a range to allow 
for multiple layer photographic emulsions with different regions of 
sensitivity. Sensitizing dyes selected to sensitize at about 780, 830, and 
880, for example, would have sensitizing effects that could overlap the 
other wavelengths. Particularly in a photographic element intended to 
provide a full color image, an overlap in sensitizing ranges would cause 
poor faithfulness in color rendition because of the spurious imaging of 
multiple layers by the same wavelength of radiation. The constructions of 
the present invention enable manufacture of high quality color 
photographic images, even where the various emulsion layers are sensitized 
to maximize sensitivity at peaks within fifty nanometers of each other. 
Any of the various types of photographic silver halide emulsions may be 
used in the practice of the present invention. Silver chloride, silver 
bromide, silver iodobromide, silver chlorobromide, silver 
chlorobromoiodide, and mixtures thereof may be used, for example. Any 
configuration of grains, cubic orthorhombic, hexagonal, epitaxial, or 
tabular (high aspect ratio) grains may be used. The couplers may be 
present either directly bound by a hydrophilic colloid or carried in a 
high temperature boiling organic solvent which is then dispersed within a 
hydrophilic colloid. The colloid may be partially hardened or fully 
hardened by any of the variously known photographic hardeners. Such 
hardeners are free aldehydes (U.S. Pat. No. 3,232,764), aldehyde releasing 
compounds (U.S. Pat. Nos. 2,870,013 and 3,819,608), s-triazines and 
diazines (U.S. Pat. Nos. 3,325,287 and 3,992,366), aziridines (U.S. Pat. 
No. 3,271,175), vinylsulfones (U.S. Pat. No. 3,490,911), carbodiimides, 
and the like may be used. 
The silver halide photographic elements can be used to form dye images 
therein through the selective formation of dyes. The photographic elements 
described above for forming silver images can be used to form dye images 
by employing developers containing dye image formers, such as color 
couplers, as illustrated by U.K. Pat. No. 478,984, Yager et al. U.S. Pat. 
No. 3,113,864, Vittum et al. U.S. Pat. Nos. 3,002,836, 2,271,238 and 
2,362,598. Schwan et al. U.S. Pat. No. 2,950,970, Carroll et al. U.S. Pat. 
No. 2,592,243, Porter et al. U.S. Pat. Nos. 2,343,703, 2,376,380 and 
2,369,489, Spath U.K. Pat. No. 886,723 and U.S. Pat. No. 2,899,306, Tuite 
U.S. Pat. No. 3,152,896 and Mannes et al. U.S. Pat. Nos. 2,115,394, 
2,252,718 and 2,108,602, and Pilato U.S. Pat. No. 3,547,650. In this form 
the developer contains a color-developing agent (e.g., a primary aromatic 
amine which in its oxidized form is capable of reacting with the coupler 
(coupling) to form the image dye. Also, instant self-developing diffusion 
transfer film can be used as well as photothermographic color film or 
paper using silver halide in catalytic proximity to reducable silver 
sources and leuco dyes. 
The dye-forming couplers can be incorporated in the photographic elements, 
as illustrated by Schneider et al. Die Chemie, Vol. 57, 1944, p. 113, 
Mannes et al. U.S. Pat. No. 2,304,940, Martinez U.S. Pat. No. 2,269,158, 
Jelley et al. U.S. Pat. No. 2,322,027, Frolich et al. U.S. Pat. No. 
2,376,679, Fierke et al. U.S. Pat. No. 2,801,171, Smith U.S. Pat. No. 
3,748,141, Tong U.S. Pat. No. 2,772,163, Thirtle et al. U.S. Pat. No. 
2,835,579, Sawdey et al. U.S. Pat. No. 2,533,514, Peterson U.S. Pat. No. 
2,353,754, Seidel U.S. Pat. No. 3,409,435 and Chen Research Disclosure, 
Vol. 159, July 1977, Item 15930. The dye-forming couplers can be 
incorporated in different amounts to achieve differing photographic 
effects. For example, U.K. Pat. No. 923,045 and Kumai et al. U.S. Pat. No. 
3,843,369 teach limiting the concentration of coupler in relation to the 
silver coverage to less than normally employed amounts in faster and 
intermediate speed emulsion layers. 
The dye-forming couplers are commonly chosen to form subtractive primary 
(i.e., yellow, magenta and cyan) image dyes and are nondiffusible, 
colorless couplers, such as two and four equivalent couplers of the open 
chain ketomethylene, pyrazolone, pyrazolotriazole, pyrazolobenzimidazole, 
phenol and naphthol type hydrophobically ballasted for incorporation in 
high-boiling organic (coupler) solvents. Such couplers are illustrated by 
Salminen et al. U.S. Pat. Nos. 2,423,730, 2,772,162, 2,895,826, 2,710,803, 
2,407,207, 3,737,316 and 2,367,531, Loria et al. U.S. Pat. Nos. 2,772,161, 
2,600,788, 3,006,759, 3,214,437 and 3,253,924, McCrossen et al. U.S. Pat. 
No. 2,875,057, Bush et al. U.S. Pat. No. 2,908,573, Gledhill et al. U.S. 
Pat. No. 3,034,892, Weissberger et al. U.S. Pat. Nos. 2,474,293, 
2,407,210, 3,062,653, 3,265,506 and 3,384,657, Porter et al. U.S. Pat. No. 
2,343,703, Greenhalgh et al. U.S. Pat. No. 3,127,269, Feniak et al. U.S. 
Pat. No. 2,865,748, 2,933,391 and 2,865,751, Bailey et al. U.S. Pat. No. 
3,725,067, Beavers et al. U.S. Pat. No. 3,758,308, Lau U.S. Pat. No. 
3,779,763, Fernandez U.S. Pat. No. 3,785,829, U.K. Pat. No. 969,921, U.K. 
Pat. No. 1,241,069, U.K. Pat. No. 1,011,940, Vanden Eynde et al. U.S. Pat. 
No. 3,762,921, Beavers U.S. Pat. No. 2,983,608, Loria U.S. Pat. Nos. 
3,311,476, 3,408,194, 3,458,315, 3,447,928, 3,476,563, Cressman et al. 
U.S. Pat. No. 3,419,390, Young U.S. Pat. No. 3,419,391, Lestina U.S. Pat. 
No. 3,519,429, U.K. Pat. No. 975,928, U.K. Pat. No. 1,111,554, Jaeken U.S. 
Pat. No. 3,222,176 and Canadian Pat. No. 726,651, Schulte et al. U.K. Pat. 
No. 1,248,924 and Whitmore et al. U.S. Pat. No. 3,227,550. Dye-forming 
couplers of differing reaction rates in single or separate layers can be 
employed to achieve desired effects for specific photographic 
applications. 
The dye-forming couplers upon coupling can release photographically useful 
fragments, such as development inhibitors or accelerators, bleach 
accelerators, developing agents, silver halide solvents, toners, 
hardeners, fogging agents, antifoggants, competing couplers, chemical or 
spectral sensitizers and desensitizers. Development inhibitor-releasing 
(DIR) couplers are illustrated by Whitmore et al. U.S. Pat. No. 3,148,062, 
Barr et al. U.S. Pat. No. 3,227,554, Barr U.S. Pat. No. 3,733,201, Sawdey 
U.S. Pat. No. 3,617,291, Groet et al. U.S. Pat. No. 3,703,375, Abbott et 
al. U.S. Pat. No. 3,615,506, Weissberger et al. U.S. Pat. No. 3,265,506, 
Seymour U.S. Pat. No. 3,620,745, Marx et al. U.S. Pat. No. 3,632,345, 
Mader et al. U.S. Pat. No. 3,869,291, U.K. Pat. No. 1,201,110, Oishi et 
al. U.S. Pat. No. 3,642,485, Verbrugghe, U.K. Pat. No. 1,236,767, 
Fujiwhara et al. U.S. Pat. No. 3,770,436 and Matsuo et al. U.S. Pat. No. 
3,808,945. Dye-forming couplers and nondye-forming compounds which upon 
coupling release a variety of photographically useful groups are described 
by Lau U.S. Pat. No. 4,248,962. DIR compounds which do not form dye upon 
reaction with oxidized color developing agents can be employed, as 
illustrated by Fujiwhara et al. German OLS No. 2,529,350 and U.S. Pat. 
Nos. 3,928,041, 3,958,993 and 3,961,959, Odenwalder et al. German OLS No. 
2,448,063, Tanaka et al. German OLS No. 2,610,546, Kikuchi et al. U.S. 
Pat. No. 4,049,455 and Credner et al. U.S. Pat. No. 4,052,213. DIR 
compounds which oxidatively cleave can be employed, as illustrated by 
Porter et al. U.S. Pat. No. 3,379,529, Green et al. U.S. Pat. No. 
3,043,690, Barr U.S. Pat. No. 3,364,022, Duennebier et al. U.S. Pat. No. 
3,297,445 and Rees et al. U.S. Pat. No. 3,287,129. Silver halide emulsions 
which are relatively light insensitive, such as Lipmann emulsions, having 
been utilized as interlayers and overcoat layers to prevent or control the 
migration of development inhibitor fragments as described in Shiba et al. 
U.S. Pat. No. 3,892,572. 
The photographic elements can incorporate colored dye-forming couplers, 
such as those employed to form integral masks for negative color images, 
as illustrated by Hanson U.S. Pat. No. 2,449,966, Glass et al. U.S. Pat. 
No. 2,521,908, Gledhill et al. U.S. Pat. No. 3,034,892, Loria U.S. Pat. 
No. 3,476,563, Lestina U.S. Pat. No. 3,519,429, Friedman U.S. Pat. No. 
2,543,691, Puschel et al. U.S. Pat. No. 3,028,238, Menzel et al. U.S. Pat. 
No. 3,061,432 and Greenhalgh U.K. Pat. No. 1,035,959, and/or competing 
couplers, as illustrated by Murin et al. U.S. Pat. No. 3,876,428, Sakamoto 
et al. U.S. Pat. No. 3,580,722, Puschel U.S. Pat. No. 2,998,314, Whitmore 
U.S. Pat. No. 2,808,329, Salminen U.S. Pat. No. 2,742,832 and Weller et 
al. U.S. Pat. No. 2,689,793. 
Particularly useful color couplers include the materials shown in the list 
of compounds as numbers 21-24. 
As previously noted, the color provided in the image produced by exposure 
of each of the differently sensitized silver halide emulsion layers does 
not have to be produced by color coupler reaction with oxidized color 
developers. A number of other color image forming mechanisms well known in 
the art can also be used. Amongst the commercially available color image 
forming mechanisms are the diffusion transfer of dyes, dye-bleaching, and 
leuco dye oxidation. Each of these procedures is used in commercial 
products, is well understood by the ordinarily skilled photographic 
artisan, and is used with silver halide emulsions. Multicolor elements 
using these different technologies are also commercially available. 
Converting the existing commercially available systems to the practice of 
the present invention could be done by routine redesign of the 
sensitometric parameters of the system and/or the addition of intermediate 
filter layers according to the teachings of the present invention. For 
example, in a conventional instant color, dye transfer diffusion element, 
the sensitivity of the various layers and/or the arrangement of filters 
between the silver halide emulsion layers would be directed by the 
teachings of the present invention, the element otherwise remaining the 
same. This would be true with either negative-acting or positive-acting 
silver halide emulsions in the element. The only major, and fairly 
apparent, consideration that must be given to such a construction is to 
insure that the placement of any filter layers does not prevent transfer 
of the diffusion dye to a receptor layer within the element. Using a 
filter which is not a barrier layer between the receptor layer and the 
dye-containing layer is the simplest way to address that consideration. 
Such a layer should not prevent migration of the diffusion dye across the 
filter layer. 
These types of imaging systems are well known in the art. Detailed 
discussions of various dye transfer, diffusion processes may be found for 
example in "A fundamentally New Imaging Technology for Instant 
Photography", W. T. Harison, Jr., Photographic Science and Engineering, 
Vol. 20, No. 4, July/August 1976, and Neblette's Handbook of Photography 
and Reprography, Materials, Processes and Systems, 7th Edition, John M. 
Stunge, van Nostrand Reinhold Company, N.Y., 1977, pp. 324-330 and 126. 
Detailed discussion of dye-bleach color imaging systems are found for 
example in The Reproduction of Colour, 3rd Ed., R. W. G. Hunt, Fountain 
Press, London, England 1975 pp. 325-330; and The Theory of the 
Photographic Process, 4th Ed., Mees and James, Macmillan Publishing Co., 
Inc., N.Y., 1977 pp. 363-366. Pages 366-372 of Mees and James, supra, also 
discuss dye-transfer processes in great detail. Leuco dye oxidation in 
silver halide systems are disclosed in such literature as U.S. Pat. Nos. 
4,460,681, 4,374,821, and 4,021,240. 
As previously noted, these existing color forming systems may be modified 
by the ordinarily skilled artisan according to the teachings of the 
present invention. For example, in the multilayer color photothermographic 
article of Example 1 of U.S. Pat. No. 4,460,681 the following steps would 
be taken to convert the element to the practice of the present invention. 
The sensitizing dye used to spectrally sensitize the first silver halide 
photothermographic emulsion would be replaced with the sensitizing dye 
used to sensitize the first emulsion layer of Example 1 of the present 
application. The filter layer described in Example 2 of the present 
application would be placed over all the coatings essential to the 
formation of color in the first deposited series of layers in Example 1 of 
U.S. Pat. No. 4,460,681. That filter layer could also function as the 
barrier layer required in the practice of that invention. The second 
series of layers essential for the formation of the next color according 
to U.S. Pat. No. 4,460,681 would then be deposited, the spectral 
sensitizing dye of that example being replaced by the spectral sensitizing 
dye of Example 1 of the present application. The remaining layers in the 
photothermographic element could then be the same as those described in 
the patent if light-sensitivity of the element (due to the 
light-sensitivity of the layers forming the third color) could be 
tolerated. If light-sensitivity is not desired, the second filter layer of 
Example 2 of the present application could be placed over the second 
color-forming layer of the photothermographic element. The third set of 
color forming layers of Example 1 of U.S. Pat. No. 4,460,681 would then be 
applied over the filter layer, and the sensitizing dye in that silver 
halide emulsion layer replaced with the spectral sensitizing dye of the 
top emulsion layer of Example 1 of the present application. Analogous 
substitution of sensitizing dyes, addition of filter layers, and/or 
modification of the relative sensitivities of silver halide layers in any 
of the other known color imaging processes could also be readily performed 
given the teachings of the present invention. Diffusion photothermographic 
color image forming systems such as those disclosed in U.K. Patent 
3,100,458A are also useful in the practice of the present invention. 
The photographic elements can include image dye stabilizers. Such image dye 
stabilizers are illustrated by U.K. Pat. No. 1,326,889, Lestina et al. 
U.S. Pat. Nos. 3,432,300 and 3,698,909, Stern et al. U.S. Pat. No. 
3,574,627, Brannock et al. U.S. Pat. No. 3,573,050, Arai et al. U.S. Pat. 
No. 3,764,337 and Smith et al. U.S. Pat. No. 4,042,394. 
Filter dyes are materials well known to the photographic chemist. The dyes 
where used, must be selected on the basis of their radiation filtering 
characteristics to insure that they filter the appropriate wavelengths. 
Filter dyes and their methods of incorporation into photographic elements 
are well documented in the literature such as U.S. Pat. Nos. 4,440,852; 
3,671,648; 3,423,207; and 2,895,955; U.K. Patent No. 485,624, and Research 
Disclosure, Vol. 176, December 1978, Item 17643. Filter dyes can be used 
in the practice of the present invention to provide room-light 
handleability to the elements. Dyes which will not allow transmission of 
radiation having wavelengths shorter than the shortest wavelength to which 
one of the emulsion layers has been sensitized can be used in a layer 
above one or more (preferably all) of the emulsion layers. The cut-off 
filter dye preferably does not transmit light more than approximately 50 
nm less than the shortest wavelength to which any of the emulsion layers 
have been sensitized. Filter dyes should also be provided with 
non-fugitive (i.e., non-migratory) characteristics and should be 
decolorizable (by bleaching in developer or heat, for example) or 
leachable (e.g., removed by solvent action of any baths). 
Other conventional photographic addenda such as coating aids, antistatic 
agents, acutance dyes, antihalation dyes and layers, antifoggants, latent 
image stabilizers, antikinking agents, and the like may also be present. 
Although not essential in the practice of the present invention, one 
particularly important class of additives which finds particular advantage 
in the practice of the present invention is high intensity reciprocity 
failure (HIRF) reducers. Amongst the many types of stabilizers for this 
purpose are chloropalladites and chloroplatinates (U.S. Pat. No. 
2,566,263), iridium and/or rhodium salts (U.S. Pat. No. 2,566,263; 
3,901,713), and cyanorhodates (Beck et al., J. 
Signalaufzeichnungsmaterialen, 1976, 4, 131). 
EXAMPLE 1 
A multi-layered IR-sensitive photographic color material was prepared by 
coating in order on resin-coated paper base the following layers: 
The first layer: a gelatin chemically sulfur-sensitized silver 
chlorobromide emulsion (88 mol % Br, 4.2% Ag, and approximately 0.6 micron 
grain size) containing anti-foggants, speed enhancers, and cyan 
color-forming couplers 23 and 24 (prepared by standard methods described 
in U.S. Pat. No. 4,363,873) was sensitized to the 880 nm region of the 
spectrum with dye 9 in the quantity of 4.0.times.10.sup.-4 mol per mol of 
silver and was coated so that the coating silver and cyan coupler weights 
are 346 mg per m.sup.2, and 517 mg per m.sup.2, respectively. 
The second layer: A gelatin interlayer containing gel hardener, U.V. 
absorber, and antioxidant was coated so that the gelatin coating weights 
are 823 mg per m.sup.2. 
The third layer: as in the first layer, the same silver chlorobromide 
emulsion containing a magenta color-forming coupler 22 was sensitized to 
the 830 nm region of the spectrum with dye 8 in the quantity of 
1.6.times.10.sup.-4 mol per mol of silver and was coated so that the 
coating silver and magenta coupler weights are 402 mg per m.sup.2 and 915 
mg per m.sup.2, respectively. 
The fourth layer: a gelatin interlayer containing hardener, U.V. absorber, 
and antioxidant was coated so that the gelatin coating weight are 1.19 
gram per m.sup.2. 
The fifth layer: the same gelatin silver chlorobromide emulsion as in the 
first layer containing a yellow color-forming coupler 21 was dye 
sensitized to the 780 nm region of the spectrum with 7 in the quantity of 
5.9.times.10.sup.-4 mol per mol of silver and was coated so that the 
coating silver and yellow coupler weights are 346 mg per m.sup.2 and 474 
mg per m.sup.2, respectively. 
The sixth layer: a gelatin interlayer containing hardener, U.V. absorber 
and antioxidant was coated so that the gelatin coating weight is 873 mg 
per m.sup.2. 
The seventh layer: a protective gelatin topcoat containing a hardener and 
surfactant was coated so that the gelatin coating weight is 1.03 
g/m.sup.2. 
The construction described above was first exposed with light from a 2950 K 
tungsten lamp giving 2400 meterCandles (mC) illuminance at the filter 
plane for 0.1 sec through a 20 cm continuous type M carbon wedge 
(gradient: 0.20 density/cm), a Wratten red selective interference filter, 
and a 780 nm near infrared glass bandpass filter. Separate samples were 
then similarly exposed using a 830 nm or a 890 nm infrared filter. After 
exposure, these samples were processed in standard Kodak EP-2 processing 
color chemistry with conditions similar to those stated in U.S. Pat. No. 
4,363,873. 
After processing, status D densitometry was measured and the results are 
shown in Table 1. The corresponding D logE curves with the effects of 
secondary exposure removed are shown in FIG. 1. At the 780 nm exposure, 
the color separation was excellent and the change in speed between layers 
was 0.7 logE or greater. At the 830 nm exposure, no yellow color was 
observed and the separation between the 830 nm layer (magenta-color) and 
the 890 nm layer (cyan-color) was 0.65 logE in speed. Only the cyan 
color-forming layer was observed at the 890 nm exposure. 
The results from the set of exposures for this color multilayer 
construction suggest that the incorporation of filter dyes within the 
interlayers is unnecessary. 
TABLE 1 
______________________________________ 
Dmin Dmax SPD2.sup.1 
AC.sup.2 
______________________________________ 
780 nm Yellow .11 2.32 3.58 2.46 
Exposed Magenta .11 2.26 2.70 2.62 
Cyan .14 1.12 2.01 * 
830 nm Yellow * * * * 
Exposed Magenta .12 2.41 2.92 3.14 
Cyan .13 1.69 2.26 2.23 
890 nm Yellow * * * * 
Exposed Magenta * * * * 
Cyan .13 2.47 2.77 3.00 
______________________________________ 
.sup.1 Relative speed measured at an absolute density of 0.075. 
.sup.2 The slope of the line joining the density points of 0.50 and 1.30 
above base + fog. 
*Not a measurable parameter. 
EXAMPLE 2 
A three-color IR-sensitive material may be prepared in the following manner 
by coating on a resin-coated paper substrate: 
(1) A first layer consisting of a silver chlorobromide emulsion (4.2% Ag) 
containing antifoggants, speed enhancers, and a cyan color-forming coupler 
23 sensitized to the 880 nm region of the spectrum with dye 9 at an 
approximate concentration of 3.0-6.0.times.10.sup.-4 mol per mol of silver 
at approximate coupler and silver coating weights of 450 to 550 mg per 
m.sup.2 and 250 to 450 mg per m.sup.2, respectively. 
(2) A second layer containing gelatin coated at approximately 0.8 to 1.2 g 
per m.sup.2, U.V. absorber, antioxidant, gel hardener and filter dye of 
the type 25, 26, 27 or 28 which has been dispersed in oil similar to a 
dispersion method as described in U.S. Pat. No. 4,363,873 at 
concentrations such that absorbance of the coated dye ranges from 0.1 to 
0.6 at 830 nm and minimum absorbance at 880 nm. 
(3) A third layer containing a silver chlorobromide emulsion similar to the 
first layer sensitized to the 830 nm region of the spectrum with the dye 8 
at an approximate concentration of 0.8-2.4.times.10.sup.-4 mol per mol 
silver and coated at silver coating weights from 300 to 500 mg per 
m.sup.2, various speed enhancers, antifoggants and a magenta-forming 
coupler 22 coated in amounts of 850 to 950 mg per m.sup.2. 
(4) A fourth layer similar to the gelatin interlayer of the second layer 
containing dyes of the type 25, 26, 27 or 28 dispersed in oil and coated 
in the gelatin such that the absorbance at 780 nm ranges from 0.1 to 0.6 
and minimum absorbance is observed at 830 and 880 nm. 
(5) A silver chlorobromide emulsion fifth layer similar to the first layer 
containing a yellow color-forming coupler 21 and dye sensitized to the 780 
nm region of the spectrum with 7 in the quantity of 
3.0-7.0.times.10.sup.-4 mol per mol silver and coated so that the silver 
and yellow coupler coating weights vary from 250 to 450 mg per m.sup.2 and 
425 to 525 mg per m.sup.2, respectively. 
(6) A sixth layer containing gelatin as an interlayer so that the gelatin 
coating weight varies from 0.8 to 1.2 g per m.sup.2, U.V. absorber, and an 
antioxidant. 
(7) A seventh layer as a protective gelatin topcoat containing a gel 
hardener and surfactant coated so that the gelatin coating weight becomes 
0.9 to 1.1 g per m.sup.2. 
The filter dyes described in this example (supra) will meet the stated 
requirements of decoloration during photographic development, 
non-diffusion through the layer to adjoining layers and the required 
spectral absorption characteristics. 
The above described construction when exposed with a tungsten lamp 
sensitometer giving 2400 mc illuminance at the filter plane for 0.1 sec. 
through a 20 cm continuous wedge (gradient: 0.20 density/cm), a Wratten 
red selective filter, and a 780 nm near infrared glass bandpass filter may 
have D logE curves similar to those shown in FIG. 2. There is some overlap 
of D logE curves for layer 5 and layer 3 when no filter dye is present in 
layer 4 (shown with solid line) and therefore, no pure color separation 
would be observed after exposure. However, after the incorporation of a 
filter dye in layer 4 with 0.4 absorbance at 780 nm, the effect on the D 
logE curve of layer 3 is shown by the dashed line and the full density of 
color would be achieved in layer 5 before exposure of layer 3. 
The same effects may be observed for exposure of the material with the 
tungsten sensitometer as described above but containing a 830 nm narrow 
bandpass filter. If no filter dye is present in layer 2 than overlap of D 
logE curves are observed. However, after the incorporation of a filter dye 
in layer 2 with 0.4 absorbance at 830 nm, the effect on layer 1 is shown 
by the dashed line of the D logE curve and thus, the full density of color 
for layer 3 would be achieved before exposure of layer 1. 
EXAMPLE 3 
As an alternative to the above color multilayer construction, the need for 
the 830 nm absorbing filter dye in layer 2 may become unnecessary if the 
speed of the emulsion layers 1 and 3 are manipulated properly as described 
below: 
(1) The first layer, as described in Example 1, containing a silver 
chlorobromide emulsion sensitized to 880 nm with dye 9 in the quantity of 
4.0.times.10.sup.-4 mol per mol silver and a cyan-forming coupler 23 
coated on a substrate such that the silver and coupler coating weights are 
346 mg per m.sup.2 and 517 mg per m.sup.2, respectively. 
(2) The second layer: a gelatin interlayer containing gel hardener, U.V 
absorber, and antioxidant coated such that the gelatin coating weight 
becomes 823 mg per m.sup.2. 
(3) The third through seventh layers: all are same in construction to those 
described in Example 2. 
The multilayer color material when exposed with the 780 and 830 nm filters 
of the tungsten sensitometer, as described in Example 2, would have D logE 
curves similar to those in FIG. 2. At the 780 nm exposure, overlap of D 
logE curves for Layer 5 and Layer 3 occurs without a filter dye present in 
Layer 4 (solid lines) and after the incorporation of the dye in Layer 4, 
pure color separation with the 780 nm exposure is achieved as shown by the 
dashed line for Layer 3. However, after exposure the 830 nm filter, full 
density of color for Layer 3 is achieved before any exposure of Layer 1 
negates the need for a filter dye in Layer 2. Good color separation was 
achieved because of the accurate speed manipulation of both these layers. 
__________________________________________________________________________ 
##STR1## 
##STR2## 
##STR3## 3 
##STR4## 4 
##STR5## 5 
##STR6## 6 
##STR7## 7 
##STR8## 8 
##STR9## 9 
Peak Minimum 
(nm) (nm) 
##STR10## 10 830 875 
##STR11## 11 850 925 
##STR12## 12 860 935 
##STR13## 13 825 890 
##STR14## 14 830 880 
##STR15## 15 795 825 
##STR16## 16 735 800 
##STR17## 17 835 870 
##STR18## 18 820 893 
##STR19## 19 740 800 
##STR20## 20 827 880 
##STR21## 21 
##STR22## 22 
##STR23## 23 
##STR24## 24 
##STR25## 25 n = 3,4 
##STR26## 26 n = 3,4 R = C.sub.2 
H.sub.5, CH.sub.2 COOH 
R.sub.1 = C.sub.2 
H.sub.4 SO.sub.3 H, 
CH.sub.3, H 
##STR27## 27 X = Br, I 
##STR28## 28 
__________________________________________________________________________ 
EXAMPLE 4 
Two diffusion transfer type constructions of two different colors was made 
as follows to show their utility according to the present invention. 
Coating 1 
A photographic element was prepared by coating sequentially the following 
three layers onto a subbed polyester film support. 
(a) A first layer consisting of yellow dye developer of structure A 
dispersed in gelatin. The coverage of dye was 5 mg/dm.sup.2 and that of 
gelatin was 7.2 mg/dm.sup.2. 
(b) A second layer consisting of a silver chlorobromide emulsion (36:64; 
Br:Cl) of 0.3 micron average grain size sensitized to 780 nm radiation by 
the addition of dye of structure B (3.times.10.sup.-4 moles dye/mole 
silver). The silver coverage was 5 mg/dm.sup.2. 
(c) A third layer consisting of 1-phenyl-5-pyrazolidinone (2.2 mg/dm.sup.2) 
dispersed in gelatin (145 mg/dm.sup.2). 
Coating 2 
Coating 2 was identical with Coating 1 except that a magenta dye developer 
of structure C replaced the yellow dye developer in the first layer and 
the silver halide emulsion was sensitized not to 780 nm but to 830 nm 
radiation by the addition of a sensitizing dye of structure D 
(5.times.10.sup.-5 moles dye per mole silver). 
Evaluation 
Five samples taken from Coating 1 were separately exposed in a sensitometer 
to radiation from a 500 watt tungsten filament lamp attenuated by a 0-4 
continuous neutral density wedge and filtered by 730 nm, 760 nm, 790 nm, 
820 nm, 850 nm or 880 nm narrow bandpass interference filters. 
The samples were laminated to Agfa-Gervaert "Copycolor CCF" dye receptor 
sheets using an Agfa-Gevaert "CP 380" color diffusion transfer processing 
machine containing 2% aqueous potassium hydroxide as processing soIution. 
The receptor sheets were separated after one minute. 
Coating 1 showed a maximum sensitivity at 760 nm resulting in a positive 
yellow image on the receptor sheet. Coating 1 exhibited no measurable 
sensitivity at 820 nm or longer wavelengths. 
This test procedure was repeated with Coating 2. In this case a sensitivity 
maximum at 820 nm was observed resulting in a positive magenta image. 
Coating 2 was 0.57 reciprocal Log exposure units less sensitive at 760 nm 
than at 820 nm and 1.70 reciprocal Log exposure units less sensitive at 
880 nm than at 820 nm. 
These layers if used in presently commercial diffusion transfer elements 
would properly function according to the teachings of the present 
invention. 
##STR29## 
EXAMPLE 5 
A single-color Infrared-sensitive photographic material was prepared by 
coating in order on resin-coated paper base the following layers: 
(1) A first-layer consisting of a chemically sensitized silver 
chlorobromide emulsion (6.8% Ag) containing antifoggants, speed enhancers 
and the magenta color forming coupler 22. The emulsion was sensitized to 
the 830 nm region of the spectrum with dye 8 at a dye concentration of 
1.1.times.10.sup.-4 mol percent mol of silver at coupler and silver 
coating weights of 1.12 g/m.sup.2 and 503 mg/m.sup.2, respectively; 
(2) A second layer containing gelatin coated at 1.20 g/m.sup.2, U.V. 
absorber, antioxidant, gel hardener and the filter dye 29, which was 
dissolved in methanol, were added to the gelation mixture and coated such 
that the filter dye coating weight was 15.1 mg/m.sup.2 ; 
(3) A third layer (as a protective gelatin topcoat) contained a gel 
hardener and surfactant coated such that the gelatin coating weight was 
1.04 g/m.sup.2. 
EXAMPLE 6 
A single-color Infrared-sensitive material was prepared as described in 
Example 5; however, dye 8 was added as a filter dye and coated so that the 
filter dye coating weight was 15.1 mg/m.sup.2 in the second layer. 
EXAMPLE 7 
A single-color Infrared-sensitive material was prepared as described in 
Example 5; however, no filter dye was incorporated into the second layer 
(control). In all examples the materials were exposed with a tungsten lamp 
sensitometer giving 2400 mc illuminance at the filter plane for 0.1 
seconds through a 20 cm continuous wedge (gradient: 0.20 density per cm), 
a Wratten red selective filter and a 830 nm near infrared, glass, bandpass 
filter. After exposure, these samples were processed in standard Kodak E-2 
processing color chemistry with conditions similar to those stated in U.S. 
Pat. No. 4,363,873. 
After processing, status D densitometry was measured and the results are 
shown in Table 1. The gel interlayers containing the filter dyes of 
Example 5 and 6 were also spread by hand onto polyethylene terephthalate, 
allowed to dry and the absorption characteristics measured on a 
Perkin-Elmer absorption spectrophotometer. These results showed that dye 
29 of Example 5 has a peak of maximum sensitization at 810 nm and a 
secondary peak at 705 nm with residual absorption from 580 nm to 900 nm. 
The filter dye used in Example 6 has a peak of maximum sensitization at 
780 nm and a secondary absorption at 700 nm with broad residual absorption 
from 520 nm to 880 nm. 
The results suggest that photographic speed of an emulsion layer can be 
manipulated by incorporating an infrared-absorbing dye in the gel layer 
above the infrared-sensitized emulsion. These filter dyes, though not 
fully processable as indicated by the higher D.sub.min for Examples 5 and 
6, decreased the photographis speed of the emulsion by approximately 0.5 
log E vs. the control Example 7). 
##STR30## 
TABLE 2 
______________________________________ 
Dmin Dmax SPD2.sup.1 
AC.sup.2 
______________________________________ 
Example 5 0.33 1.92 3.45 1.82 
Example 6 0.30 1.85 3.55 1.56 
Example 7 0.18 2.23 3.97 2.27 
(control) 
______________________________________ 
.sup.1 Relative speed measured at an absolute density of 0.75. 
.sup.2 The slope of the line joining the density points of 0.50 and 1.30 
above base + fog. 
EXAMPLE 8 
A full-color Infrared-sensitive material was prepared by coating in order 
on resin-coated paper base the following layers: 
The first layer: a gelatin chemically sensitized silver chlorobromide 
emulsion (6.7% Ag) containing anti-foggants, speed enhancers, and cyan 
color-forming coupler 23 was sensitized to the 880 nm region of the 
spectrum with dye 9 in the quantity of 1.6.times.10.sup.4 mol per mol of 
silver and was coated so that the coating silver and cyan coupler weights 
were 412 mg/m.sup.2 and 634 mg/m.sup.2, respectively. 
The second layer: a gelatin interlayer containing gel hardener, U.V. 
absorber, and antioxidant was coated so that the gelatin coating weight 
was 828 mg/m.sup.2. 
The third layer: a gelatin chemically sensitized silver chlorobromide 
emulsion (6.6% Ag) containing anti-foggants, speed enhancers, and magenta 
color-forming coupler 22 was sensitized to the 830 nm region of the 
spectrum with dye 8 in the quantity of 8.9.times.10.sup.-5 mol per mol of 
silver and was coated so that the coating silver and magenta coupler 
weights were 492 mg/m.sup.2 and 1.12 g/m.sup.2, respectively. 
The fourth layer: a gelatin interlayer containing hardener, U.V. absorber, 
antioxidant and the filter dye 29, which has been dissolved in methanol 
and added to the gelatin mixture, was coated such that the filter dye and 
gelatin coating weights were 8.3 mg/m.sup.2 and 0.65 g/m.sup.2, 
respectively. 
The fifth layer: a gelatin chemically sensitized silver chlorobromide 
emulsion (6.7% Ag) containing antifoggants, speed enhancers, and yellow 
color-forming coupler 21 was dye sensitized to the 780 nm region of the 
spectrum with dye 7 in the quantity of 3.4.times.10.sup.-4 mol per mol of 
silver and was coated so that the coating silver and yellow coupler 
weights were 497 mg/m.sup.2 and 679 mg/m.sup.2, respectively. 
The sixth layer: a gelatin interlayer containing hardener, U.V. absorber, 
and antioxidant was coated so that the gelatin coating weight was 876 
mg/m.sup.2. 
The seventh layer: a protective gelatin top-coat containing a hardener and 
surfactant was coated so that the gelatin coating weight was 1.04 
g/m.sup.2. 
EXAMPLE 9 
A multi-color Infrared-sensitive material was prepared as described in 
Example 8; however, dye 8 was added as a filter dye and coated so that the 
filter dye coating weight was 8.3 mg/m.sup.2 in the fourth layer. 
EXAMPLE 10 
A multi-color Infrared-sensitive material was prepared as described in 
Example 8; however, no filter dye was incorporated into the fourth layer 
(control) and the gel coating weight was 1.20 g/m.sup.2. 
In examples 8-10, all materials were exposed to a tungsten sensitiometer as 
described in Example 5-7, except separate samples were then similarly 
exposed using a 780 nm or a 890 nm infrared filter. 
The sensitometric results are shown in Table 1. The filter dye gel 
interlayer (layer 4) from examples 8 and 9 were hand-spread onto 
polyethylene terephthalate as desribed above. The absorption curves 
suggest that absorption of 780 nm and 830 nm light would be similar for 
the dye interlayer of example 8 and that less absorption of the 830 nm 
light vs. 780 nm light would be observed for the dye interlayer of example 
9. The sensitometric results for the multi-layer material of these 
examples also suggests this observation. At the 780 nm exposure, the loss 
in speed for layer 3 (magenta color) relative to the non-filtered layer 3 
of example 10 (control) is approximately 0.25 logE and 0.36 logE for 
example 9 and 8, respectively. At the 830 nm exposure, the loss in speed 
for layer 3 vs. the control (example 10) was minimal for example 9 (less 
dye interlayer filtering) vs. example 8 (0.9 logE vs. 0.27 logE). 
Also, loss in photographic speed is observed for layer 5 (yellow-color, 780 
nm sensitized of examples 8 and 9) vs. the non-filter dye interlayer of 
example 10 (control) at the 780 nm exposure even though the absorption of 
780 nm light occurs in layer 4 after the initial non-filtered 780 nm 
exposure of layer 5. These results suggest that for the non-filtered 
material of example 10 the 780 nm light passes through all layers, reaches 
the base and then is reflected back through all layers so that each layer 
of the photographic material is exposed twice. With the incorporation of 
the filter dyes into layer 4, the first pass of 780 nm light through the 
multilayer materials of example 8 and 9 is non-filtered for layer 5 (780 
nm sensitized) so that the first exposure occurs, then as the residual 780 
nm light passes through layer 4, some of the light is absorbed. After this 
filtration, the remaining 780 nm light then continues through the layers, 
reaches the base, and is reflected back through the layers until more of 
this light is absorbed or filtered again (effective double filtration) 
while passing through layer 4 (filter layer) to reexpose the 780 nm layer 
(layer 5). Thus, the total amount of effective 780 nm exposure will be 
less for multilayer materials containing the filter dye interlayers vs. 
non-filter dye interlayer constructions and therefore, the observed speed 
of the 780 nm sensitized (layer 5) will be less because of this total 
lower amount of exposure. 
The results from the set of exposures for the color multilayer 
constructions of example 8-10 suggest that the incorporating of filter 
dyes can effectively manipulate the photographic speeds of emulsion 
layers. 
##STR31## 
TABLE 3 
______________________________________ 
Dmin Dmax SPD2.sup.1 
AC.sup.2 
______________________________________ 
780 nm Exposure 
Example 8 
yellow .20 2.28 5.68 2.70 
magenta .19 1.85 4.89 1.93 
Example 9 
yellow .19 2.25 5.79 2.80 
magenta .18 1.99 5.00 2.00 
Example 10 
yellow .13 2.25 6.03 2.78 
magenta .14 2.16 5.25 2.17 
830 nm Exposure 
Example 8 
magenta .20 2.13 3.22 2.27 
cyan .31 * * * 
Example 9 
magenta .18 2.23 3.40 2.27 
cyan .25 * * * 
Example 10 
magenta .13 2.22 3.49 2.27 
cyan .15 * * * 
890 nm Exposure 
Example 8 
cyan 0.30 .68.sup.3 
* * 
Example 9 
cyan 0.24 .71.sup.3 
2.54 * 
Example 10 
cyan .15 .80.sup.3 
2.58 * 
______________________________________ 
.sup.1 Relative speed measured at an absolute density of 0.75 
.sup.2 The slope of the line joining the density points of 0.50 and 1.30 
above base + fog. 
.sup.3 Number does not reflect absolute maximum density of layer but limi 
of exposure at designated exposure conditions. 
*Parameter not measurable 
EXAMPLE 11 
A multi-layered IR-sensitive photographic color material was prepared by 
coating in order on resin-coated paper base the following layers: 
The first layer: A gelatin/chemical sensitized silver chlorobromide 
emulsion (88 mol %, Br, 6.7% Ag, and approximately 1.0 micron grain size) 
containing antifoggants, speed enhancers, and the cyan color-forming 
coupler 23 was sensitized to the 880 nm region of the spectrum with dye 9 
in the quantity of 1.6.times.10.sup.-4 mol per mol of silver. The emulsion 
was coated so that the silver and coupler coating weights were 417 mg per 
m.sup.2 and 636 mg per m.sup.2, respectively. 
The second layer: A gelatin interlayer containing gelatin hardener, U.V. 
absorber, and antioxidant was coated so that the gelatin coating weight 
was 828 mg per m.sup.2. 
The third layer: A gelatin/chemically sensitized silver chlorobromide 
emulsion (88 mol % Br, 6.7% Ag, and approximately 0.5 micron grain size) 
containing anti-foggants, speed enhancers, and the magenta color-forming 
coupler 22 was sensitized to the 830 nm region of the spectrum with dye 8 
in the quantity of 8.8.times.10.sup.-5 mol per mol silver. This was coated 
so that the silver and coupler coating weights were 492 mg per m.sup.2 and 
1.12 g per m.sup.2, respectively. 
The fourth layer: A gelatin interlayer containing hardener, U.V. absorber, 
and antioxidant was coated so that the gelatin coating weight was 1.20 g 
per m.sup.2. 
The fifth layer: The same gelatin silver chlorobromide emulsion as in the 
first layer, containing the yellow color-forming coupler 21, was dye 
sensitized to the 780 nm region of the spectrum with dye 7 in the quantity 
of 3.4.times.10.sup.-4 mol per mol silver. This was coated so that the 
silver and coupler coating weights were 542 mg per m.sup.2 and 748 mg per 
m.sup.2, respectively. 
The sixth layer: A gelatin interlayer containing hardener, U.V. absorber 
and antioxidant was coated so that the gelatin coating weight was 876 mg 
per m.sup.2. 
The seventh layer: A protective gelatin topcoat containing a hardener and 
surfactant was coated so that the gelatin coating weight was 1.04 g per 
m.sup.2. 
EXAMPLE 12 
A multi-layered IR-sensitive photographic material was prepared as 
described in Example 11, except that the 780 nm sensitized layer (fifth 
layer) was coated as the third layer and the 830 nm sensitized layer 
(third layer) was coated as the fifth layer. 
EXAMPLE 13 
A multi layered IR-sensitive photographic material was prepared as 
described in Example 11, except that the 780 nm sensitized layer (fifth 
layer) was coated as the first layer and the 880 nm sensitized layer 
(first layer) was coated as the fifth layer. 
The constructions described above were first exposed with the output from a 
780 nm 2 mw laser diode sensitometer. The sensitometer is capable of 
writing laser raster exposures onto film strips through a circular wedge, 
neutral-density filter (metal vacuum-deposited, 0-4 neutral density). 
Separate samples were then similarly exposed using a 820 nm or a 880 nm 
laser diode source in the sensitometer. After exposure, these samples were 
processed in standard Kodak EP-2 processing color chemistry. 
After processing, status D densitometry was measured and the corresponding 
D logE curves were produced. These results show that full yellow color 
density can be achieved for the 780 nm sensitized layers of Examples 11-13 
before the required exposure images the slower (in speed) 830 nm 
sensitized emulsion layer. Also, the results show that regardless of 
placement (layer 1, for Example 13, layer 3 for Example 12, and layer 5 
for Example 11) within the multi-layer construction. Unique color 
separation was achieved between the 780 and 830 nm sensitized layers. With 
820 nm laser exposure, a magenta color density of 2.0 is achieved for 
Examples 11 and 12 before exposure images the slower (in speed) 880 nm 
sensitized emulsion layer. This unique color separation would also be 
attained if the 880 nm sensitized layer (layer 5) of Example 13 was slowed 
down in speed further. Surprisingly, regardless of placement of the 830 
and 880 nm sensitized layers within the construction, color separation was 
achieved. With the 880 nm exposure, only the 880 nm sensitized layers of 
Examples 11-13 are exposed regardless of placement within the 
construction. The results from these examples show that if sufficient 
speed separation (780 nm layer faster in speed that the 830 nm layer, the 
830 nm layer faster in speed than the 880 nm layer) is maintained between 
the emulsion layers, then unique color separation is achieved.