CA1299424C - Radiographic element exhibiting reduced crossover - Google Patents

Abstract

RADIOGRAPHIC ELEMENT
EXHIBITING REDUCED CROSSOVER
Abstract of the Disclosure A double coated radiographic element is disclosed comprised of a dye coated between an emulsion layer and a support to reduce crossover to less than 10 percent. The dye is present in the form of microcrystalline particles, yet is capable of being decolorized in less than 90 seconds during processing.

Description

~2~2~

RAD I OGRAPHI C F~LEMENT
EXHIBITING REDl5CED CROSSOVER
Field of the Invention The invention rel~te~ to r~tdiogr~phy. More 5 specificAlly, the invention relates tD ~ouble ~06tted ~ilver h~tlide r~diogr~tphic element~ of the type employed ln combin~tion with lnten~ifying screen~.
Bsck~round of the Invention While silver halide photogrQphic elements are c6tpable of directly recording X ray exposures, they ~tre more re~pon~ive to light within the visible spectrum. It has become ~tn e~tabli~hed practice to con~truct Duplitlzed~ (double co~ted) r6tdiogr6tphic elements in which silver halide emul~ion lAyers ~re coated on oppo~ite 3ides of ~t film support ~nd to s6tndwich the radiogr6tphic element between intenslfying screen p~tirs during ima8ing. The inten~ifylng ~creens cont6tin phosphors th6tt ~tbsorb X r~di~tion 6tnd emlt light. This llght is transmitted to the silver hAlide emulsion l~yer on the Qd~acent f~ce of the film support. The result is thAt di6tgno~tic r~tdiogr~tphic imAgin~ ls Achieved at slgnificAntly reduced X-rEty exposure levels.
An Art recogni~ed dlfficulty with employing double co~ted radiogr~tphlc element~ 6ts described above i9 that some li~ht emltted by each screen p~tsses through the tr~tnsparent film support to expose the ~ilver hallde emulsion layer on the opposite side of the support to ll~ht. Thi~ results in reduced im~tge shArpne~s, and the effect is referred to in the art a~
cro~sover.
A vAriety of ~tpproQche~ hAve been suggested to reduce crossover, 6ts illustrf~tted by Research Di~closure, Vol. 184, August 1979, Item 18431, Section V. Cross-~ver Exposure Control. Rese~trch Disclosure is published by Kenneth M~son Public6t- tions, Ltd., Emsworth, Hampshire P010 7DD, Engl~nd.

One ~pproach to reducing cro~over ha~ been to di~solve a filter dye in one or more of the hydrophilic colloid l~yer~ forming the r~dio~r~phic element. Such dyes must, of course, be ~elected to minlmize re~idu~l density ~stain) in the lm~ge be~ring r~diogrsphic element. A pervasive problem with diss~lved dyes has been their mlgr~tion to the l~tent im~ge forming silver halide gr~in~, whether co~ted directly in the im~ge forming emulsion l~yers or in underlying layers. This h~s resulted in loss of photogr~phic ~peed, which, of course, runs directly counter to the gener~l ~im in ~dopting a double co~ted radiogr~phic element form~t in the fir~t inst~nce. Thus, where this ~ppro~ch has been followed, ~ b~l~nce of reduced photogr~phic ~peed ~nd residu~l crossover h~s been ~ccepted. Although mord~nts h~ve been employed to reduce dye migration, they h~ve not been effective ln preventing loss of photogr~phic speed snd h~ve further proved dis~dv~nt~geous in incre~sing the bulk of the w~ter perme~ble l~yers of the rAdiogr~phic elements, thereby incre~sing the processing time required to produce ~ processed element th~t i9 dry to the touch. Th~ di~solved dye ~ppro~ch to crossover reduction is illustr~ted by Doorsel~er U.K. P~t.
Spec. 1,414,456 Rnd Bollen et ~1 U.K. Pat. Spec.
1,477,638 ~nd 1,477,639.
To reduce dye mlgration to the im~Be forming silver halide 8r~ins ~ v~ri~nt ~pproRch has been to ~d~orb the dye to the surf~ces of silver h~lide gr~in~ other thQn those employed in im~ging. Thl~
~ppro~ch reduces speed 109~, but has the dis~dv~nt~ge o~ requiring silver h~lide grQins to be pre~ent in ~ddition to tho~e required for l~tent lm~ge form~tion. Further, ~n ~dded silver h~lide gr~in popul~tion incre~es vehicle requirements ~nd correspondingly incre~ses drying times. Millik&n et al U.K. Pat. Spec. 1,426,~77 illustrates thi3 approach applied to a specialized photogrnphic lma~ing ~ystem in which a ~llver h~lide gr~in popUlHtion ~ 3 present in addition to the ~rain population which ls relled upon to produce a latent image.
The most successful appro~ch to crossover reduction yet reallzed by the art has been to employ double coated radiogr~phic element~ containin~
spectrally ~en~itized hlgh spect ratio tabular gr~in emulsion~ or thin intermediate aspect ratio tabular grain emul~ions, illustrated by Abbott et al U.S.
P~tent~ 4,425,425 and 4,425,426, respectively.
Crossover levels below 20 percent (but well above lO
percent) are reported.
Summary of the Invention In one a~pect this invention i~ directed to a radiographic element comprised of a film support capable of tran~mittin8 r~diation to which the rsdiogrRphic element is responsive having opposed ma~or f~ces. Processing solution permeable hydrophilic colloid layers are present including, coated on each oppo~ed ma~or face, at le~st one ~ilver halide emul~ion layer capable of responding to electromagnetic radiation in the v~sible portion of spectrum and at leAst one other hydrophilic colloid layer interposed between the emulsion layer ~nd the support~ A dye is dispersed in at least one of the interposed hydrophilic colloid layers capable of 3~ Hb~orbing visible radiation to which the rAdiographic element ls respon~ive to reduce crus~over and cap~ble of being decolorized in a processin8 solution.
The radiographic element is characterized in th~t the dye i~, prior to proce~lng, in the form of microcrystalline particles present in a concentration 3ufficient to rP-duce crossover to less th~n lO
percent and i~ capable of being substantially 31 ~g$~4 decolorized in less than 90 seconds during processing.
The pre~ent invention offers significant and unexpected advantages over the prior st~te of the srt. Crossover i~ reduced below levels heretofore succe~fully schieved in the art ~nd without desensiti~ation of l~tent image formin~ silver halide grains. The extremely low crossover levels real1zed have been made pos_ible by di3covering that dyes incorporated in ~ radiogrsphic element in the form 10 microcry~talline particle~ c~n be nevertheless satlsfactorily decolorized durin~ the very ~hort processln~ interv~l conventionaily employed in prepAring radiographic images. By employing the crossover reducing dyes in microcrystalline form migration of the dyes to l~tent im~ge forming silver hallde grains surfaces and resulting desensitization of these grains i~ obviated. Further, the preRent invention permits simpler rsdiographic element construction than i~ possible with radiographic elements employing a nonimaging ~ilver halide grains to provide dye adsorption surfaces. Still further, the microcrystAlline form of the dyes ~llows superior spectral ~dsorption profiles to be reslized ag compared to the sRme or chromophorically simllar dyes ad~orbed to silver halide grain surfaces.
Finally, the crossover reduction advantsges of the present invention ~re fully compAtible with both the crossover reduction And other known advAntages of hiKh aspect ratio and thln, inter~ediate aspect ratlo t~bular grain silver halide emulsions.
Brief DescriPtion of the DrAwin~s Figure 1 is ~ schemutic view of an ~ssembly consisting of a radiographic element and a psir of intensifying screens.
Figures 2 snd 3 are plots of denslty as an ordinate versus wavelen8th a9 an ~bscissa of ~ 2~

proce~sed control and exsmple rQdiographic elements.
Descri~tion of Preferred Emhodiments Referrin8 to Figure 1, in the ~ssembly shown ~ r~diogrnphic element 100 acrording to thi~
invention i~ posltioned between a p~ir of light emitting intensifying screen~ 201 ~nd 202. The r~diogr~phlc element support i9 compri~ed o a r~diographic support element 101, typically tr~n~parent or blue tinted, c~p~ble of tran~mitting ~t least ~ portion of the light to which it is ~xpoqed and option~l, similarly tr~n~mi~sive subblng l~yer units 103 ~nd 105, e~ch of which can be formed of one or more ~dhesion promoting l~yers. On the first ~nd second oppo~ed ma~or f~ces 107 ~nd 109 vf the support formed by the subbing layer units ~re crosqover reducing hydrophilic colloid layers 111 end 113, respectively. Overlying the crossover reducing l~yers 111 ~nd 113 are light recording l~tent im~ge forming silver halide emulsion layer units 115 ~nd 117, re~pectively. E~ch of the emulsion lsyer units is formed of one or more hydrophilic colloid l~yers including ~t lesst one sllver halide emulsion lsyer.
Overlying the emul~ion l~yer unit~ 115 and 117 ~re optionsl protective overcoat lsyer~ 119 and 121, ~5 re~pectively. All of the protectlve l~yers und hydrophllic colloid l~yers are permenble to processing solution~.
In use, the Assembly is imagewise exposed to X-r~diation. The X r~dlRtion is princip~lly ~bsorbed 30 by the intensifying screens 201 ~nd 202, which promptly emit light H9 Q direct function of X ray expo~ure. Consldering Eirst the light emitted by screen 201, the light recording latent imsge forming emulsion layer unlt 115 is positioned ad~acent this screen to receive the light which it emits. Bec~use of the proximity of the acreen 201 to the emulsion l~yer uni~ llS only minimal light scattering occurs 2~

before latent ima8e formlng absorption occur~ in this layer unit. Hence light eml3~ion from screen 201 form~ a sharp image in emul~ion layer unit 115.
~owever, not ~11 of the light emltted by screen 201 is absorbed with~n emul~ion l~yer unit 115. This rema~ning light, unless otherwise absorbed, will reach the remote emul~ion layer unit 117, resulting in a highly un~harp image bein8 formed in thi~ remote emuls~on layer unit~ Both crossover reducing layers 111 and 113 ~re interposed between the ~creen 201 and the remote emul~ion layer unit and are capable of intercepting snd attenuatlng this remainin~ light. Both of these layers thereby contribute to reducing crossover exposure of emul~ion layer unit 117 by the ~creen 201.
In an exactly ~nalogou~ manner the screen 202 produces a sh~rp image in emul~ion layer unit 117, and the light absorbing layers 111 Rnd 113 similRrly reduce crossover exposure of the emulsion layer unit 115 by the screen 202. It is app~rent that either of the two cro~sover reducing layers employed alone can effectlvely reduce cro~qsover exposures from both screens. Thus, only one light absorbing layer iq required. In a varlant form the crossover reducing layers on opposite sides of the support can be u~ed to absorb radiation from dlfferent regions of the spectrum. For exAmple~ R
light absorbing dye cun be present in one crossover reducing layQr while an ultraviolet (UV) Rbsorber is present in the remainine crossover reducing layer.
For manuPQcturing convenience dual co~ted radiographlc elements most commonly employ identical coating~q on opposite ma~or faces of the support.
Following exposure to produce a stored latent image, the radiographic element 100 ls removed from ~ssociation with the intensifying screens 210 and 202 and processed in a conventional manner. That ~ 2~

i~, the r~diographic element i~ brouBht into cont~ct with an aqueou~ alkaline developer, ~uch a3 ~
hydroquinone-Phenidone~(l-phenyl-3-pyrazolidone) developer having a pH of 10.0, ~ speclfic form of which i~ illu~tr~ted in the example~ below. The alXaline developer permeate~ the hydrophilic colloid layers, converting the silver halide emul~ion layer latent ima8e to a viewable silver ima~e ~nd simultaneDu31y decolorizing the cro~over reducing layers. Conventional post development ~teps, such as stop bath cont~ct, fixing, and washing can occur.
Since the crossover reducing l&yer~ csn be decolori~ed in le~ than 90 second~ followin~ contact with an aqueou~ alkaline proces~in~ ~olution of pH
lO.0, the radiographic elements of thi~ invention are fully compatible with conventional radio~raphic element processing, such as in an RP-X-Omat~
processor.
The radiogrflphic elements of the present invention offer advantages in crnssover reduction by employing one or more cro~sover reducing layers comprised a hydrophilic colloid employed Q~ a dispersing vehicle and a particul~te dye. The concentration of the dye pre~ent i9 chosen to impart an optical denslty of at least 1.00 ~t the peak wavelen~th of emulsion sensitivity. Slnce it 19 conventional practice to employ intensifying screen-radiographic element combinatlon~ in which the peak emulsion sensltivity mQtches the peak light emission by the intensifyin~ screens, it follows that the dye al90 exhibit~ ~ density of at least l.00 ~t the wavelength of peak emi~sion of the intensifyin~
screen. Since neither screen emissions nor emul~ion sensitivities are confined to a single wavelength, it is preferred to choose partlculate dye~, including combinations of particulate dyes, capable of imp~rtin~ a den~ity of 1.00 or more over the entire 9~ ~2 ~

~pectral region of ~ignificant ~ensltivity ~nd emi9~ion. For radiographic elements to be u~ed with blue emitting inten~ifying ~creen~s, guch ~ thD~se which employ c~lcium tung~tate or thulium activated lanth~rlum oxybromlde pho~phors, it i~ generally preferred that the particulate dye be ~elected to produce ~n optical den3ity of at le~t 1.00 over the entire spectral region of 400 to 500 nm. For radiographic elements intended to be u~ed with green emitting inten~ifyin~ screen~, such AS those employing rare earth (e.g., terbium) activated g~dolinium oxysulfide or oxyhalide pho~phors, it i~
preferred thst the p~rticulate dye exhibit ~ density of at lesst 1.00 over the spectr~l region of 450 to 550 nm. To the extent the w~velength of emission of the screens or the ~ensitivitie~ of the emul~ion lAyerq are re~tricted, the ~pectr~l region over which the particulate dye must ~lso effectively absorb light i~ corre~pondingly reduced.
While particulate dye optic~l densities of 1.00 chosen es described above are effective to reduce cro~over to le~s than 10 percent, lt is ~pecifically recognized that particul~te dye denAities c~n be lncreased until radiographlc element croqsover is effectively eliminated. For ex~mple, by increasing the particulate dye concentration ~o that it illlpartS R den~ity of 10.0 to the radiogrsphic element, cros~sover i9 reduced to only 1 percent.
Since there is a direct relationship between the ~ye concentrstion ~nd the opticsl density produced for a ~iven dye or dye combination, precise optlc~l density selections c~n be schieved by routine ~election procedures. Because dye.s v~ry widely in their extinction coefficients ~nd ~bsorption profiles1 it is recogni~ed that the weight or even molar concentration~ of p~rticulate dye~ will vsry from one dye or dye combination selection to the nPxt.

~2 ~

The size of the dye particles is chosen to facilltate co~tin~ and rapifl decoloriz~tion of the dye. In gener~l ~maller dye particles lend themselve~ to more uniform costing~ ~nd more r~pid decoloriz~tion. The dye p~rticles employed in ~11 in3t~nces h~ve a mean diameter of less than 10.0 ~m ~nd prefer~bly le3s than 1.O ~m. There is no theoretic~l ~imit on the minimum ~ize~ the dye particleq cfln tQke. The dye p~rticles c~n be mo~t conveniently formed by crystQllization from ~olutiDn in 3izes r~nging down to ~bout 0.01 ~m or less.
Where the dyes ~re initi~lly crystRllized in form of p~rticle~ l~rger than desired for use, conventional technique~ for ~chieving qm~ller p~rticle ~izes c~n be employed, such as bRll millin~, roller milling, s~nd milling, Rnd the iike.
An import~nt criterion in dye selection is their Qbility to rem~in in pRrticulate form in hydrophilic colloid l~yer~ of rAdiogrRphic elements.
20 While the hydrophilic colloids c~n t~ke any of v~rious conventionQl forms, such as Qny o~ the forms set forth in Re~eQrch Di~closure, Vol. 1-76, December 1978, Item 17643, Section IX. Vehicles flnd vehicle extenders, the hydrophilic collold lAyers Rre most commonly gelAtin and gelRtin deriv~tives.
Hydrophilic colloids ~re typically coRted as aqueous solutions in the pH ran8e of from ~bout S to 6, most typicslly from 5.5 to 6.0, to eorm radlogrQphic element lsyers. The dyes which ~re selected for use in the pr~ctice of this inventlon ~re those which ~re cRpsble of remRining in p~rtlcul~te form ~t those pH
levels ln Qqueous solution~.
Dyes which by resson of their chromophoric make up flre inherently ionic, such QS cyanine dyes, ~s well 89 dye~ which contQin substituents which Rre ionic~lly dissociRted in the above-noted pH r~nge~ of coRting m~y in individuQl instRnce~ be ~ufficiently in~oluble to satisfy the requirement~ of this invention, but do not in 8eneral con~titute preferled cla3ses of dy0~ for u~e in the pr~ctice of the invention. For example, dye~ with ~ulfonlc scid ~ubstituent~ are normally too soluble to s~ti~fy the requirements of the invention. On the other hand, nonionic dyeq with carboxylic acid groups (depending in ~ome instance3 on the ~pecific substitution location ~f the carboxylic ~cid group~ sre in general insoluble under aqueous acid coatin~ conditions.
Specific dye ~election~ can be made from known dye characteri~tic~ or by observing solubilities in the pH range of from 5.5 tG 6.0 at normal layer co~ting temperatures -e.~., at a reEerence temperature of 40C.
Preferred particulate dye~ are nonionic polymethine dyes, which include the merocy~nine, oxonol, hemioxonol, ~tyryls, and arylidene dyes.
The merocyanine dyes include, ~oined by a 20 methine linka~e, at least one basic heterocyclic nucleus and at least one Qcidic nucleu~. Basic nuclei, ~uch ~s azolium or azinium nuclei, for example, include those derIved from pyridinium, quinolinium, iqoquinolinium, ox~zolium, pyrazolium, pyrrolium, indollum, ox~diazolium, 3H- or lH-benzoindolium, pyrrolopyridinium, phen~nthrothi azolium, and acenaphthothiazolium quaternary sAlts.
Exempl~ry of the b~sic heterocyclic nuclei are those satisfyin~ Formul~e I and II.
(I) I_ _ z _ _I
=C - (L=L) -N-R
~II) q _ _ Q~_ _ _ -C=L - (L~L)q N-R
where Z represents the element~ needed to complete 8 CyC~ iC nucleu~ derive~ from b~ic heterocyclic nitrogen compound~ such ~8 oxazollne, ox~zole, benzox~zole, the n~phthoxazoles (e.g., n~phth[~ d]ox~zole, naphth[~,3-d]ox~ole, and naphth[l,2-d]ox~zole), ox~diRzole, 2- or 4-pyridine, 2- or 4-quinoline, l- or 3-isoquinollne, benzoquino-.
line, lH- or 3H-benzoindole, and pyrRzole, which nuclei m~y ~e substituted on the ring by one or more of ~ wide v~riety of ~ubstituents such ~ hydroxy, the hQlogens (e.g., fluoro, chloro, bromo, ~nd iodo), ~lkyl groups or substituted nlkyl groups (e.g., methyl, ethyl, propyl, isopropyl, butyl, octyl, dodecyl, octndecyl, 2-hydroxyethyl, 2-cy~noethyl, and trifluoromethyl), Qryl groups or substltuted ~ryl ~roup~ (e.g., phenyl, l-naphthyl, 2-n~phthyl, 3-c~rboxyphenyl, und 4-biphenylyl), ar~lkyl group~
(e.g., benzyl nnd phenethyl), alkoxy groups ~e.g., methoxy, ethoxy, ~nd i~opropoxy), aryloxy group~
(e.g., phenoxy and l-n~phthoxy), alkylthio groups (e.g., methylthio ~nd ethylthio), ~rylthio groups (e.g., phenylthio, ~-tolylthio, ~nd 2-n~phthylthio), methylenedioxy, cysno, 2-thienyl, styryl, nmino or substituted smino group~ (e.~ nilino, dimethyl-Qmino, diethylQmino, Rnd morpholino), Qcyl groups,(e.g., formyl, acetyl, benzoyl, and benzenesul~onyl);
Q' repre~ents the elements needed to complete a cyclic nucleu~ derived from basic heterocyclic nitrogen compounds such QS pyrrole, 30 pyrazole, indazole, snd pyrrolopyridine;
R represents alkyl groups, aryl group~, slkenyl groups, or nrQlkyl groups, with or wikhout ~ubstituents, (e.g., c~rboxy, hydroxy, sulfo, alkoxy, ~ulfnto, thiosulfQto, phosphono, chloro, ~nd bromo substituents);
L is in e~ch occurrence independently selected to represent Q substituted or unsubstituted methine ~roup - e.~ CR = groups, wher~ R
represents hydrogen when the methine group i~
un~ub~tituted Rnd most commonly represents ~lkyl of from 1 to 4 c~rbon atom~ or phenyl when the methine group i~ ~ub~tituted; ~nd q i9 0 or 1.
Merocy~nine dye~ link one of the b~sic heterocyclic nuclei described above to ~n acidic keto methylene nucleu~ through a methine link~ge, where the methine groups can take ~he form -CR =
de~cribed above. The 8reater the number of the methine groups linking nuclei in the polymethine dyeq in general ~nd the merocyanine dyes in particular the longer the ~b~orption w~velengths of the dyes.
Merocy~nine dye~ link one of the basic heterocyclic nuclei deqcribed above to ~n ~cidic keto methylene nucleus through a methine linkage a~
described sbove Exempl~ry acidic nuclei are those which sati~fy Formula III.
(III) o l!_ --~\ 2 where Gl represents ~n alkyl group or substituted Qlkyl group, an sryl or substituted ~ryl group, ~n aralkyl group, ~n ~lkoxy group, an aryloxy group, ~
hydroxy group, Rn smino group, or R substltuted R~ino ~roup, wherein exempl~ry substituents c~n take the various forms noted in connectlon wlth Formul~e VI
and VII;
G c~n represent any one of the groups listed ~or Gl ~nd in ~ddition cRn represent ~ cyano group, ~n alkyl, or arylsulfonyl group, or ~ group repre~ented by -C-Gl, or G2 t~ken together with Il o c~n represent the element~ needed to complete a cyclic acidic nucleu~ ~uch ~ tho~e der~ved from ~,4-oxazolidlnone ~P~g.~ 3-ethyl-2,4-oxazolidindi-one), 2,4-thiazolidindlone (e.g., 3-methyl-~,4-thi-~zolidindione~, 2 thio-2,4-oxa~olidindione (e.g., 3-phenyl-2-thio-~,4-oxazolidindione), rhodanine, ~uch A~ 3-ethylrhodsnine3 3-phenylrhod~nine, 3-(3-di-methylsmlnopropyl)rhod~nine, and 3-c~rboxymethyl-rhod~nine, hyd~ntoin (e.g~, 1,3-diethylhydQntoin ~nd 3-ethyl-1-phenylhyd~ntoin), 2-thiohyd~ntoin (e.g., l-ethyl-3-phenyl-2-thiohydQntoin, 3-heptyt-1-phenyl-2-thiohyd~ntoin, and aryl~ulfonyl-2-thiohydAntoin), 2-pyrazolin-5-one, 3uch 89 3 methyl-1-phenyl-2-pyrAzolin-5-one and 3-methyl-l-(4-cArboxyphenyl)-2-pyra~olin-5-one, 2-i~ox~z~lin-5~one (e.g., 3-phenyl-2-i~oxRzolin-5-one), 3,5-pyrazoli~indione (e.g., 1,2-diethyl-3,5-pyrazolidindione and 1,2-diphenyl-3,5-pyr~zolidindione), 1,3-indAndione, 1,3-diox~ne-4,6-dione, 1,3-cyclohexanedione, 20 barbituric acid (e~g., l-ethylbarbituric ~cid and 1,3-diethylbQrbituric acid), and 2-thiobarbituric acid (e.g., 1,3-diethyl-2-thiobArbituric acid and 1,3-bis(2-methoxyethyl)-2-thiobQrbituric acid).
U~eful hemioxonol dyes exhibit ~ keto methylene nucleu~ a9 shown ln Formula III and a nucleus ~ ~hown in Formul~ IV~
(IV) ~G4 where G and G4 may be the same or diPEerent and mAy represent ~lkyl, sub~tituted alkyl, aryl, substituted ~ryl, or arslkyl, ~ illustrAted for R ring sub~tituents in Formula X or G And G tsken together complete A ring system derived from R cyclic secondAry amine, such as pyrrolidine, 3-pyrroline, ~2~

piperidine, piperazine (e.g., 4-methylpiperazine and 4-phenylp~perAzine), morpholine, 1,2,3,4-tetrQhydro-quinoline, dec~hydroquinoline, 3-~z~bicyclo[3,2,2]no-nane, indDlin2, ~zetidine~ and haxahydro~zepine.
5Exemplary oxonol dyes exhibit two keto methylene nuclei ~ ~hown in Formul~ olned through one or higher uneven number of methine ~roup~.
U~eful ~rylidene dye~ exhibit a ~eto methylene nucleu~ a~ shown in Formula III ~nd ~
nucleu~ ~ shown in Formul& V ~oined by ~ methine linkage a~ described above cont~ining one or a higher uneven number of methine groups.
(V) 15~ \G4 where G ~nd G are as previously defined.
A specifically preferred cl2s~ of oxonol dyes for use in the pr~ctice of the invention are the oxonol dyes s~ti~Eying Formul~ VI.
(VI) O OH
H02C~ ~7=CH-CH=CH~ C02H, \~ ~ \ 1 t wherein R ~nd R2 e~ch independently represent ~lkyl oÇ from 1 to 5 c~rbon atom~.
ExemplQry of ~pecific preÇerred oxonol dyè~
~re those set forth below in TQble I.
T~ble I
O OH

35 H02C \._./ ~ _ / 2 wherein Dye Rl R2 l/0 CH3 CH3 A ~peciflc~lly preferred clRss of ~rylidene dyes for u~e in th2 pr~ctlce of the invention are the arylidene dye3 9ati~fying Formul~ VII.
(VII) R3 A --C tcH=cH ~ ~ t /~ ¢ 2 ; wherein \R6 A represent~ ~ ~ubstituted or un3ubstituted acidlc nucleus havin~ ~ carboxyphenyl ~ubstituent selected from the group consi~tin~ of 2-pry~zolin-5-ones free of any sub~tituent bonded thereto through carboxyl group, rhod~nines; hyd~ntoins; 2-thiohyd~n-toin~; 4-thiohyd~ntoins; 2,4-oxa~olidindiones;
2-thio-2,4-ox~zolidindiones; isoxazolinones;
20 bArblturic~; 2-thiob~rbituric~ ~nd ind~ndiones;
R repre~ents hydrogen, alkyl of l to 4 carbon ~toms or benzyl;
R and R , each independently, repre~ents alkyl or ~ryl; or t~ken to~ether with R , R , N, and the c~rbon atoM~ to which they are attached represent the ~toms needed to complete a ~ulolidene rin8;
R represents H, alkyl or aryl;
R ~nd R , a~ch independently, represent~ H or RS taken to~ether wit11 Rl; or R taken together with R each may repre~ent the ~toMs nece~sary to complete a 5 or 6 membered rin8; ~nd m i~ 0 or 1.
Exemplary of specific preferred arylidene dye~ ~re tho~e set forth below in T~ble~ II and III.

~ \C=CH(-CH~CH)-~ t ~

5(HOOC)x =C~ 4 n \,=~ \R~

x ~-max - - 1 2 3 4 Ring -m~x (10-4) Dye R , R R R # Site n (nm~

10 l/A CH3 HCH3 4 466 3.73 2/A C2H5 HCH3 1 4 0 471 4.75 3/A n-C~IH9 HCH3 1 4 0 475 4.50 15 4/A CH3 C 2H5 ~ 4 508 5.23 5/A i-C3H70C ~ 2CH3 CH3 1 4 0 430 3.34 6/A CH3 HCH3 2 3,5 0 457 3.78 7/A C2H5 HCH3 2 3,5 0 475 4.55 8/A n-C4Hg HCH3 2 3,5 0 477 4.92 9/A i C3H70C~o2H CH3 2 3,5 0 420 3.62 25 10/A i-C3H70C~o2CH3 3 2 3,5 0 434 3.25 ll/A CH3 HCH3 l 4 l 516 4.62 R

30 12/A i-C3H70C CH2 H CH3 1 4 0 420 3.94 13/A CH3 H C CH3 l 4 0 573 5.56 l4/A CH3 H COOEt 1 4 1 576 5.76 15/A CH3 H CH3 2 3,5 1 506 3.90 16/A CH3 H COOEt I 4 0 502 4. 83 17fA CH3 11 COOEt 2 3,5 1 560 5.25 18/A C2H5 H COOEt 1 4 0 512 6 . 22 l9/A CH3 H CF3 1 ~ 0 507 4~ 58 20/A CH3 H Ph 1 4 0 477 4. 54 lo R
21/A CH3 H C CH3 1 4 0 506 5 . 36 Table III
p~3 3 X C=CH--.~ t ~
( HOOC ) x C\R4 \ . _ ./

x ~ax c--max DYe R3 R4# Rng. Site (nm) (10-4) 22/A H CH31 4 500 S . 82 ZO 23/A H CH32 3,5 502 5.47 As indicated above, it i~ speclfically contemplRted to employ a UV absorber, either blended with the dye in each of cros~over reducing layers 111 ~nd 113 or confined to one crossover reducing layer with the dye being conPined to the other crossover reducin~ layer. Any conventlonal UV ~bsorber can be employed for tnis purpose. Illustr~tive u~eful UV
absorbers are those discloqed in Research Di~clo3ure, Item 18431, clted above, Section V~ or Re~e~rch Disclo~ure, Item 17643, cited ~bove, Section VIII.C.
-Preferred UV absorbers are those which either exhibitminimal ~b~orption in the visible portion of the ~pectrum or are decolorized on processing simllarly the cros~over reducin~ dyes.
Ap~rt from the cro~sover reducing l~yers 111 and 113 described above, the remainin~ features of the du~l co~ted radiogr~phic elements can t~ke Hny convenient convention~l form~ Such conventional radiogrsphic element fe~tures are illustrated, for example, in Research Disclo~ure, Item 18431, cited ~bove. Other conventional fe~ture~ common to both silver h~lide radiographic elem2nts and photogrsphic element~ sre dlsclosed in Rese~rch Disclo~ure, Item 17643, cited ~bove.
Radiographic element~ accordlng to this invention h~ving highly de~irable imagin~
characteriQtics ~re those which employ one or more tabular Brain silver h~lide emulsion~.
Preferred radiographic elements Qccording to the present lnvention ~re those which employ one or more high aspect r~tio tabular gr~in emulsions or thin, intermediate ~sp~-ct ratio tabular grain emul~lons. Pre~erred t~bulRr erain emul~ions for use in the r~diographic element~ of this invention ~re those in which tabul~r silver h~lide grains h~ving 8 thickne~s of less than 0.5 ~m (preferably less th~n 0.3 ~m and optimally less th~n 0.2 ~m) have ~n average aspect ratio of greater than 5:1 (prefer~bly greater than 8:1 ~nd optimally at lea~t 12:1) ~nd account for gre~ter th~n 50 percent (preferQbly greater than 70 percent snd optimally 8reater than 90 percent) of the total pro~ected ~rea of the silver halide gralns present in the emulslon. Preferred blue and minus blue ~pectr~l sensitizing dyes a~ well as optimum chemical and spectral sensitizations of tabular silver hallde gr~ins ~re disclosed by Ko$ron et Al U.S. Patent 4,43~,520~
The preferred radlographic elements of this invention are tho~e which employ one or more of the cros~over reducing l~yer~ described above in combination with tabular grain latent image $orming emul~ions. Preferred rAdiographic element ~nd 2~

t~bul~r gr~in ~ilver h~lide emul~ion fe~ture~ ~re disclo~ed in Abbott et al U.S. P~tent~ 4,425,425 ~nd 4,425,426 and Dicker~on U.S. P~tent 4,414,304.
Radiogr~phic element~ can be con~tructed according to 5 thi~ inventlon in which tabular ~r~in ~ilver halide emulsion l~yer~ ~re co~ted nesrer the support thRn nont~bul~r grain 3ilver h~lide emul~ion l~yer~ to reduce cro~over~ ~ illustrated by Sugimoto publi~hed European P~tent Applic~tion 0~084,637. By 10 employing t~bul~r 8r~in emul~ions, which in themselve~ reduce cro~sover in combination w~th the cro~over reducing l~yers provided by thi~ invention radiographic element~ exhibitlng extremely low cros~over level~ cun be ~chieved while al~o ~chievin~
15 high photographic speed, low levels of grRnularit hi~h silver covering power ~ and rRpid proce~sing espabilities deemed highly de~ir~ble in r~diogrRphy.
ExamPles The invention i~ further illustr~ted by the 20 followlng examples.
Examples 1 through 6 The following ex~mples compsre the perform~nce of double co~ted radio~r~phic elements exposed u~lng blue emitting thullum activRted r 25 lRnth~num oxybromide phosphor inten~ifying ~creens.
The r~dio~rQphic element~ were identical, except f~r the choice of the cro~sover reducing mQteri~ls employed between the emul~lon l~yer Qnd the support on e~ch ma~or ~urface.
The dye ~ati~fying the requirement~ of the invention waA Dye l/A ~hown ~bove in Table II. The dye wa~ employed in ~ pQrticulate Porm, the meRn diameter of the dye particles being 0. oa ~m.
TRrtr~zine Yellow (C.I. Acid Yellow 23-C.I.
35 13.065~, herelnafter referred to ~ C-l, was selected control exemplary of dyeq which are w~ter soluble Qnd nonbleachRble taught by the ~rt to be u~ed as a cros~over redu~ing dye in ~ double co~ted radiographlc element. To reduce wandering of the dye cationic mord~nt poly~l-methyl-2-vinylpyridinium ~-toluene sulfonate (hereinAfter referre~ to a3 M-l) 5 was u~ed with the dye in a weight ratio of 5 part~ of mordant per part of dye.
Carey Lea Silver, hereinafter referred to a~
CLS, was ~elected a~ a control exemplary of ~
particulate material which i9 neither water ~oluble nor bleachable under conditions compatible wlth ~llver imaging.
A ~eries of double coated r~diographic element~ identical, except for the choice and concentration oÇ crossover reducing material li~ted 15 below in Table IV, were prepared a~ follows:
Onto each side of a blue-tinted polyester film support was coated a gelatin hydrophilic colloid layer containing the cro~over reducing material.
The gelatin coating coverage wa~ O.ll g/m2.
One control element was constructed with the same hydrophilic colloid layers, but without a crossover reduclng material bein~ present. This element is referred to a~ C-O.
An emul~ion layer wa~ coated over e~ch hydrophilic colloid layer. The blue recording ~ilver bromide emulsion layer w~s coated at a coverage of 2.2 g/m2 silver ~nd 2.2 g/m2 ~el~tin.
Over each emul~ion layer was co~ted a gelatin overcoat ~t a coverage of O.9l g/m2.
The hydrophilic colloid layers (including the emulsion l~yers) were h~rdened with bis(vinylsul fonylmethyl) ether at l.O% of the gel~tin weight.
To permit cro~sover determin~tion~, ~amples of the du~l coated radiogr~phic elements were exposed 35 with A single inten~ifying ~creen placed in contact with one emulslon layer. Black paper w~s plRced ~ain~t the other emulsion side of the sample. The ~g~

X-r~diation ~ource wa~ ~ Picker VTX653 3-phase X-r~y m~chine, with a Dunlee High-Speed PX1431-CQ~150 kVp 0.7/1.4mm focus tube.
Expo~ure w~ m~de at 70 XVp, 32mA~, ~t dlstance of 1.40 m. Flltr~tion w~s with 3 mm Al equivAlent (1.25 inherent ~ 1.75 Ql); H~lf vRlue LQyer (HVL) - 2.6 mm Al. A ~6 ~tep Al w~dge wa~
u~ed, differin$ in thickne~ by 2 ~m per tep.
Proces~ing of the exposed film wa~ in e~ch in~t~nc~ undert~ken using ~ proces~or commerci~lly ~vailAble under the trademerk Kodsk RP X-Omat Film Processor M6A-N. The developer employed exhibited the following formul~:
Hydroquinone 30 Phenidone~ 1.5 g KOH 21 g NaHC03 7.5 g K2S03 44.2 g N~2S205 12.6 g N~Br 35 g 5-Methylbenzotriazole 0.06g Glut~r~ldehyde4.9 g W~ter to 1 liter/ pH 10Ø
The fllm w~s in contact with the developer in e~ch 5 in~t~nce for le~s th~n 90 ~econds.
The density of the ~ilver developed in e~ch of the sllvQr h~lide emul~ion l~yers, the emulsion lsyer AdJscent the intensifying screen ~nd the nonRd~cent emulsion l~yer sep~r~ted from the intenslfying screen by the film support. By plotting density produced by e~ch emulslon lAyer ver~us the steps of the step-wedge ~ me~sure of exposure), ~
sensltometric curve w~ Bener~ted for e~ch emulsion l~yer. A hi~her density wss produeed for ~ given exposure in the emulqion ne~rest the itensifylng screen. Thus, the two sensltometric curves were offset in ~peed~ A~ three different denslty levels in the relatively 3tr&ight line portion~ of thc sensitometric curve~ between their toe ~nd ~houlder~
the difference in Rpeed (~ 108 E~ between the two qensitometric curve~
5 w~ mea~ured. These dlfference~ weEe then averAged ~nd u3ed in the following equ~tion to c~lcul~te percent cro~sover:
% Cro~sover = 1 X 100 antllog (~ log E) +l 10 Percent cro~over i~ reported in T~ble IV below.
Rel~tive speed reported in T~ble IV i~ the speed of the emulsion l~yer neare~t the support.
TQble IV
Relstive Cros30ver Reducer % Cros~over SPeed St~in (D/sq. m) (Fig.2) None 20 70 C-0 (.07) l/A (Exsmple~ ll 59 (.07) CLS (Control) 3 59 20(.07) C-l (Control) 9 52 (.14) l/A (Ex~mple) 6 56E-l/A
(.14) CLS (Control) 3 61 CLS
(.14) C-l (Control) 5 51 C-l All of the cros~over reducing m~teri~ls of T~ble IV were shown c~pable of reducing cro~over below 10 percent.
The mord~nted w~ter soluble dye C-l and the CLS both gave un~ccept~ble re~ults, since in neit~er instAnce did bleRching occur on processing. Further, the dye C-l by re~son of itq w~ndering ch~rRcteristic reduced photoKr~phic speed signi~ic~ntly, even thou8h it w~s incorpor~ted with a mord~nt to ~revent w~ndering.
The dye l/A w~s entirely decolorized during proces~ing. From Figure 2 it cRn be 3een th~t the denslty of the element ~fter proce~sin~ w~
essenti~lly ~imil~r to the element l~cking -~3-cros~over reducing materi~l. At the s~me time the c~pability of cro~soYer reduction below 10 percent w~s demon3trated. Some lo~s of photographic ~peed WR~ observ2d, but lt i~ to be noted that, since the purpo~e of a cro~sover reducing Agent i~ to prevent portion of the li~ht emitted by the 3creens from expo~in~ the emulsion lsyer~, some reduction in photogrsphic ~peed is inherent in cro~sover reduction.
Thi~ ex&mple demonstr~te~ the ~sti~factory 10 perform&nce of a ble~chAble p~rticulate dye to reduce crossov2r without producing dye st~in ~n the proce~sed r~diogr~phic element ~nd with only minim~l imp~ct on im~ging speed. The conkrol cro~soYer reducing m~terial~ were un~cceptable bec~use of their high dye ~t~in, and the control dye was unacceptable in producing an incre~ed lo~ in im~ging speed.
Further, the control dye required the further incorporation of ~ mord~nt, which added to the drying lo~d on the proc0ssor. Without the mordant being 20 present the imRging speed loss would have been significantly higher.
Ex~mPles 7 through 12 The procedure of Ex~mples 1 through 6 was repe~ted, except th~t magenta dyes were substituted for testing~ green sensitized r~diogrsphic emulsions were employed, ~nd green emitting intensifying ~creens, Kod~k L~nex Regulcr~ screens, were employed.
The dye satisfying the requirements of the invention w~s Dye 4/A shown ~bove in TRble II. The dye w~ employed in a partlculQte ~orm, the me~n diameter of the dye particles bein8 0.2 ~m.
Acid M~8ent~ ~C.I. Acid Violet l9-C.I.
42,685), hereinRfter referred to as C-2, w~s selected ag ~ control exemplary of dyes which flre w~ter ~oluble ~nd ble~chable taught by the art to be used cro~sover reducing dye in a double co~ted r~diogrAphic element. To reduce w~ndering of the dye the c~tionlc mord~nt M-l W~3 employed in ~ 5 p~rts mordant to 1 p~rt dye weight ratio.
1,3-Bis[l-~4-sulfonylphenyl)-3-c~rboxy-2-pyr~z olin-5-one-4] trimethine oxonol, disodium ~lt, herein~$ter referred to ~ C-3, w~s selected ~5 ~
control exempl~ry of m~gent& dyes whlch ~re water ~oluble ~nd nonble~ch~ble. Dye C-3 differed from dye 10 disclo3ed on p~ge 5 of U~K. P~t. Spec. 1,414,456 only in that the nuclei were ~oined by 3 methine 8roUPg instead of 5 (to shift ~bsorpti~n into the desired green spectr~l region). To reduce wAndering of the dye c~tionic mordsnt M-l w~ a~ain employed in ~ 5 p~rts mord~nt to 1 p~rt dye weight ratio.
The results are summ~rized below in T~ble V.
Table V
Relative Cros~over Reducer % Cros~over SPeed St~in (D/m ) (Fig.3 20None 19 113 C-0 (.045) 4/A (Example) 11 101 (.045) C-2 (Control) 19 92 (.045) C-3 (Control) 14 98 (.09) 4/A (Ex~mple) 7 97 E-4/A
25(.Og) C-2 (Control) 15 87 C-2 (.09) C-3 (Control) 10 91 C-3 From T~ble V it ls ~pp~rent th~t the control crossover reducin~ dyes were inferior, both in terms of rel~tlvely lower crossover reduction ~nd in terms of rel~tively 8re~ter speed loss impQrted. From Flgure 3 lt c~n be seen th~t the dye~ 4/A ~nd C-2 exhlblted essentlAlly slmil~r ble~ching ch~r~cter-i~tics. The dye C-3 produced ~ signific~ntly hlgher dye ~t~in~

APPENDIX
A-l. PreparQtion of 1,3-Bis~l-(4=carboxyPhenyl)=

oxonol ~9Y~ lL~
1-(p-C~rboxyphenyl)-3-methylpyr~zolone (21.8 g), ethanol (100 ml), and triethylamine (14.6 g or 20 ml) were combined and boiled under reflux $or 30 minutes. The mlxture w~s chilled and then combined with 200 ml methsnol, then 40 ml concentrAted lO hydrochloric ~cid. A red precipit&te formed immediately. The mixture w~ stirred at room temper~ture for 15 minute~ ~nd filtered. The precipitate was wsshed with 300 ml ethsnol, 1000 ml meth~nol, 1000 ml ether, Rnd then sir dried to yield a dry weight of 12.4 g.
The precipit~te cont~ining the dye W&S then pur~fied through a number of w~shing snd dissolu-tion/recrystallizstion steps. The precipitste w~s first slurried in 500 ml refluxing glacisl ~cetic acid, cooled to room tempersture, filtered, w~shed with 250 ml scetic Qcid, 250 ml H20, 250 ml methsnol, snd then dried. It wss then dissolved in 100 ml hot dimethylsulfoxide ~nd cooled to 40C.
300 ml methsnol wss added, upon which a red precipitste formed, which W~9 filtered, wsshed wlth methanol, ~cetone, snd ligroin, ~nd dried. Thi~
precipit~te ws~ dissolved in 200 ml methanol ~nd 6 ml (4.38 g) trlethylsmine and hested to reflux. 4.8 ml of concentrsted hydrochloric scld was added and a fine red precipitate wss forrned. The solution w~s filtered while hot and the precipitate wa~ washed with meth~nol Qnd scetone snd dried. The preclpitste was then dissolved in 8 refluxing mixture o$ 200 ml ethsnol ~nd 6.0 ml (4.38 g) triethylsmine. 9.0 g of ~odium iodlde di~olved in 50 ml methsnol wss sdded.
Upon cooling to room temperature, ~ red precipitate formed. The mixture W89 chilled in ice for one hour, then filtered. The precipitate was washed wit 42~

eth~nol, ligroin snd dried ko yield the ~odium s~lt of the dye.
The sodium ~alt of the dye wa~ di~solved in 200 ml water with rapid ~tirring. 6.0 ml concentr~ted hydrochloric acid wa~ added ~nd ff fluffy red preclpit~te formed. The mixture wa9 filtered ~nd the precipit~te w~ w~hed with w~ter, methanol, acetone, and ligroin, arld dried to yield Dye 1/0~
A-2. PreParation of 1-(3,5-Dlc~rboxyphenY12-4-(4-dimethyl~minobenzylidene~-3-methyl-2-pYr~zo-lin-5-one (Dye 6/A) A olution of ~odium nltrlte (35.8 gm, 0.52 mol) in water (75 ml) wa~ added to ~ ~lurry of 5-~minoisophth~lic acid (90.6 gm, 0.50 mol) in 4.8 15 molar HCl (500 ml) at 0C over 15 minutes with stirring. Stirring wa~ contlnued for one hour st 0-5C and the ~lurry wa3 then added to a solution of sodium ~ulfite (270 gm, 2.2 mol) in water (1.21) all ~t one tlme, with ~tirring, at 2C. The resulting 20 homogeneou~ solution wa~ heated At 50-60C for 45 minutes. ConcentrAted HCl (60 ml) wa~ ~dded and the re~ction mixture WRS heated further at gOC for one hour. After cooling to room temperature another portion of concentrated HCl (500 ml) wa9 added. The solid w~ isolcted by filtration ~nd washed on Q
funnel with ~cidified water, EtOH and ligroin in succe~sion. The off-white ~olid WQ~ di~olved in a solution of NaOH (76 gm, 1.85 mol in 600 ml water).
This solution W~9 ~ub~equently ~cidified with glacial 30 acetic acid (1~6 ml, 3.0 mol) to yield a thlck slurry. This wa~ i~ol~ted by filtrution, ws~hed on the funnel with water, EtOH and llgroin in succes~ion, and thorouehly dried in a vscuum oven at 80~C, and 10 mm Hg. The mp wa~ above 300C. The NMR
and IR spectrR were con~istent with the ~tructure for 5-hydrazlno-1,3-benzenedicarboxylic acid. The product gave a po~itive teqt for hydrazine with Tollen~' reagent.

-~7-A ~lurry compo~ed of the product 5-hydr~zino-1,3-benzenedic~rboxylic ~cid (64.7 gm, 0.33 mol), ethyl~cetoacetate (50.7 gm, 0.39 mol) and gl8cial acetic ~cid (250 ml) was stirred ~nd refluxed for 22 hours. The mixture WAS COGled to room temperature and the product which had precipitated wa~ isol~ted by filtration, waahed with water, EtOH, Et20, and ligroin in succe~ion ~nd thoroughly dried in a v~cuum oven at 80C and 10 mm Hg. The mp 10 of the qolid was above 310C. The NMR ~nd IR spectra were cons~tent with the assi8ned 3tructure. The product 8ave a negative test with Tollens' rea~ent.
The C,H ~nd N elemental anQly~es were in ~greement with tho~e calculated for the empirical formula for 1-(3,5-dicsrboxyphenyl)-3-methyl-2-pyr~zoline-5-one~
A 31urry composed o$ 1-(3,5-dicarboxy-phenyl)-3--methyl-2-pyrazoline-5-one (44.6 gram~/ 0.17 mol), 4 dimethylaminobenzaldehyde (26.~ grams, O.lB
mol) ~nd EtOH (500 mL) was he~ted ~t reflux for three 20 hours. The reaction mixture was chilled in ice ~nd the resulting crude orange product wa9 isolated by filtration and washed with EtOH (200 mL). The product was purified by three repetitive slurrie~ of the solid in acetone (1.4 1) ~t reflux ~nd filtering to recover the dye. The mp of the product was above 310~C. The NMR ~nd IR spectrfl were consistent with the structure as~igned. The C, H and N element~l flnalyses were in ~8reement wlth those calculated for the empirical formulA for the dye.
30 A-3- PreP~r~tion of (l-(4-Carbo~yE__nYl)-4-C4 dimeth~laminobenzylidene)--3-methYl--2--pyrazo lin-5=one (Dye l/A) A slurry composed of 1-(4-carboxyphenyl)-3-methyl-2-pyrazolin-5-one (21.8 gm, 0.10 mol), 4-dimethylaminobenzsldehyde (14.9 gm, 0.10 mol) snd EtOH (250 ml) WA9 heated at reflux ~or two hours.
The reaction mixture W89 cooled to room temperature resulting in a crude or~nge product which was -2~
i~olsted by filtr~tion. The pro~uct wa3 then w~shed with ether 2nd dried. The product w~s purified further by m~king ~ ~lurry of the ~olid in EtOH (700 ml) ~t refluxing temper~ture ~nd filterlng the ~lurry to recover the dye. The treatment wa3 repeated. The mp of the product w~ above 310~C. The NMR and IR
~pectra were con~istent with the ~tructure ~R~igned.
The C,H, ~nd N elemental analyse~ were in Q~reement with those calculQted for the empiricQl formul~. 0 A-4. Prepar~tion of 1-(4-Carboxyphenyl)-4-~4-dimethylaminoclnn~mylidene)-3-methYl-2-pyr-azolin-5-one (Dye ll/A) 1-(4-C~rboxyphenyl)-3-methyl-2-pyrazolin-5-one (2.18 gm, 0.010 mol), 4-dimethylaminocinn~maldehyde (1.75 gm, 0.010 mol) and gl~cial ~cetic acid (10 ml) were mixed together to form Q slurry. It wa~ heated to reflux with ~tirring, held at reflux for five minutes and then cooled to room temper~ture. EtOH
(20 ml) wa9 ~dded to the resction mixture which w~
20 heated ~gain to reflux, held there for five minute~
and cooled to room temper~ture. The product w~
isol~ted by filtr~tion, w~shed in ~ucce~ion with ethanol ~nd ligroin, and dried. The reaction WQ~
repe&ted twice on the ~Ame ~cQle ~nd the products obtained were all combined. They were trested further by fir~t ~lurryin~ in refluxing EtOH (150 ml), i~ol~ting the ~olid by filtr~tion while hot, Qnd then ~lurrying in refluxing MeOH (200 ml) Qnd i~olating it QgQin, while hot, by filtrQtion. The mp 30 waq 282-284C. The NMR ~nd IR ~pectr~ were consi~tent for the structure ~igned. The C,H ~nd N
element~l Qnaly~e~ were in Qgreement with tho~e calcul~ted for the empirlc~l formula of the dye.
The invention h~ been de~cribed in det~il 3S with pQrticul~r reference to preferred embodlment~
thereof, but it will be under~tood th~t variation ~nd modification~ c~n be effected within the 3pirit snd ~cope o the invention.

Claims (10)

1. A radiographic element comprised of a film support, capable of transmitting radiation to which said radiographic element is responsive, having opposed major faces, processing solution permeable hydrophilic colloid layers including, coated on each opposed major face, at least one silver halide emulsion layer capable of responding to electromagnetic radiation in the visible portion of the spectrum and at least one other hydrophilic colloid layer interposed between said emulsion layer and said support, a dye dispersed in at least one of said interposed hydrophilic colloid layers capable of (1) absorbing visible radiation to which said radiographic element is responsive to reduce crossover and (ii) being decolorized in a processing solution, characterized in that said dye is, prior to processing, in the form of microcrystalline particles present in a concentration sufficient to reduce crossover to less than 10 percent and is capable of being substantially decolorized in less than 90 seconds during processing.

2. A radiographic element according to claim 1 further characterized in that said dye is initially present in a concentration sufficient to impart an optical density of at least 1.00 at the wavelength within the visible spectrum of peak emulsion sensitivity.

3. A radiographic element according to claim 2 further characterized in that said dye is a yellow dye.

4. A radiographic element according to claim 3 further characterized in that said dye exhibits an optical density of at least 1.00 over the spectral region of from 400 to 500 nm.

5. A radiographic element according to claim 2 further characterized in that said dye is a magenta dye.

6. A radiographic element according to claim 3 further characterized in that said dye exhibits an optical density of at least 1.00 over the spectral region of from 450 to 550 nm.

7. A radiographic element according to claim 1 further characterized in that said dye particles exhibit a mean diameter of less than 1 µm.

8. A radiographic element according to claim 1 further characterized in that at least one of said interposed hydrophilic colloid layers contains an ultraviolet absorber.

9. A radiographic element according to claim 1 further characterized in that said dye when decolorized imports a residual density to said radiographic element of less than 0.02.

10. A radiographic element comprised of a blue tinted transpsrent film support having opposed major faces, processing solution permeable hydrophilic colloid layers including, coated on each opposed major face, at least one silver halide emulsion layer capable of responding to electromagnetic radiation in the visible portion of spectrum and at least one other hydrophilic colloid layer interposed between said emulsion layer and said support, a yellow or magenta dye dispersed in at least one of said interposed hydrophilic colloid layers coated on each said major faces capable of absorbing visible radiation to which said radiographic element is responsive to reduce crossover and capable of being decolorized in a processing solution, characterized in that said dye is prior to processing in the form of microcrystalline particles of less than 1 µm in mean diameter present in a concentration sufficient to impart an optical density of at least 1.00 over a 100 nm spectral interval including the wavelength of peak silver halide emulsion sensitivity within the visible spectrum, thereby reducing crossover to less than 10 percent, and is capable of being substantial-ly decolorized to a density of less than 0.01 in less than 90 seconds in a hydroquinone-Phenidone?
(1-phenyl-3-pyrazolidone) developer having a pH of at least 10.