Abstract: According to an example, a three-dimensional (3D) printer may include a delivery device to deposit a light absorbing agent onto selected areas of a layer of build material particles, in which the light absorbing agent absorbs light having wavelengths that are around the ultraviolet wavelength range. The 3D printer may also include a light source to apply light onto the selectively deposited light absorbing agent and the layer of the build material particles, in which the light absorbing agent absorbs light around the ultraviolet wavelength range from the applied light and becomes heated to a temperature that causes the build material particles upon which the light absorbing agent has been deposited to melt and to fuse together following cessation of the application of the light.

Abstract: A method is described for producing an imaged lithographic printing plate, wherein the developer comprises a hydrophilic polymer comprising (m1) structural units derived from at least one compound comprising both a polyalkylene oxide chain and a free radical polymerizable group, and (m2) structural units derived from at least one compound copolymerizable with the free radical polymerizable group of (i) and comprising at least one functional group with pKs<5.

Abstract: In accordance with one aspect of the present invention, a method for recording holographic data in an optical data storage medium is provided. The method includes (i) providing an optical data storage medium including: (a) a thermoplastic polymer matrix, (b) a latent acid generator, (c) a non-linear sensitizer, and (d) a reactant including a latent chromophore. The method further includes (ii) irradiating a volume element of the optical data storage medium with an interference pattern, said interference pattern including an incident radiation having a wavelength and an intensity sufficient to cause upper triplet energy transfer from the non-linear sensitizer to the latent acid generator, thereby generating an acid, wherein the latent acid generator is substantially non-responsive to said incident radiation.

Abstract: A reversible multicolor thermal recording medium which is free from fogging and has sharp contrast even after recording and erasing are performed repeatedly, and a recording method using the same are provided. A reversible multicolor recording medium is provided, which includes recording layers each containing a plurality of reversible thermal coloring compositions having different coloring tones, formed to be separated from and stacked on a surface direction of a supporting substrate; and the plurality of reversible thermal coloring compositions containing light-to-heat transforming materials which absorb infrared rays having different wavelength ranges to generate heat, respectively; wherein an absorption peak wavelength of the light-to-heat transforming material contained in the recording layers becomes the longest wavelength at the layer formed nearest the supporting substrate, and becomes a shorter wavelength as the layer is closer to the surface layer in the stacked order.

Abstract: The invention concerns a process for producing a security feature and a print medium which is equipped in that respect, which affords the possibility of not having to implement any change and in particular mechanical change in the surface of the card body. In that respect the substrate includes at least one change-over substance which by irradiation with light of a given wavelength experiences an irreversible change in color from a starting color to a final color, wherein the substrate in the initial condition is so irradiated with a controlled light beam of that wavelength, in particular a laser light beam that, due to the change in color caused thereby in the change-over substance, an image which can be recognized with the naked eye is produced within the volume of the substrate.

Abstract: Composites, methods, and systems for production of multi-color images which are developable at various wavelengths are disclosed and described. The color forming composite can include a first color forming layer having a first polymer matrix, a first color former, and a first developer where the first color former and the first developer can be in separate phases within the first color forming layer; a second color forming layer having a second polymer matrix, a second color former, and a second developer where the second color former and the second developer can be in separate phases within the second color forming layer; and at least one radiation absorber. The radiation absorber can be present in at least one of the first or second color forming layers. Additionally, the first color forming layer can have a first extinction coefficient that is higher than the second extinction coefficient of the second color forming layer.

Abstract: A method and apparatus for manufacturing a color conversion filter. The method includes forming a color filter layer on a transparent substrate. A coloring matter layer containing color conversion coloring matter and an optical radical generating agent are formed on the substrate and the filter layer. The coloring matter layer is exposed to coloring matter decomposition light applied through the substrate and the filter layer. The coloring matter layer also is exposed to auxiliary ultraviolet light applied from the side of the coloring matter layer. This forms a color conversion layer at a position corresponding to the filter layer. The optical radical generating agent is heat vaporized. The color conversion coloring matter is decomposed by light whose wavelength is outside a range that the color filter layer transmits. The coloring matter decomposition light includes a wavelength component that decomposes the color conversion coloring matter.

Abstract: A developing solution includes at least one of a compound represented by formula (I) and a compound represented by formula (II) and being at pH 2 to 10: wherein, in the formula (I) and (II), R1 to R10 each independently represent one of a hydrogen atom an an alkyl group; “1” represents an integer of 1 to 3; and X1 and X2 each independently represent one of a sulfonate salt, a sulfate monoester salt, a carboxylate salt and a phosphate salt, provided that the total sum of the carbon atoms in R1 to R5 and the total sum of the carbon atoms in R6 to R10, respectively is 3 or more.

Abstract: Disclosed herein are methods and apparatus for providing markings upon objects, including the read side of an optical information media, where the markings do not substantially interfere with object, including the use of the optical information media. This invention discloses use of a coating, marking schemes, printing of markings with UV light, as well as methods and apparatus for reading and deciphering said marking. Included is an authentication scheme, where the marking may be used as a lock to limit access to information contained in an optical information media.

Abstract: The application, according to a desired image, of an absorbance controlling composition to a receiver having an imaging layer comprising a radiation absorbing component, such as a dye or pigment, with spectral absorbance properties susceptible to change on treatment with the absorbance controlling composition provides a method of imaging by which a desired image may be formed on the receiver, for example by jetting a solution of the absorbance controlling composition onto the receiver.

Abstract: A color image-forming material capable of drawing an image by infrared laser exposure and excellent in image visibility, storage stability and white light stability, and an on-press development or non-processing (non-development) type lithographic printing plate precursor ensuring high sensitivity and high press life and being excellent in image visibility, on-press developability and the like, are provided, which are a color image-forming material comprising an image recording layer capable of drawing an image by infrared laser exposure, the color image-forming material forming a color image without passing through a development processing step after image recording, wherein the image recording layer comprises (A) an infrared absorbent, (B) a cyclic color-forming compound having a cyclic structure within the molecule and forming a dye by a ring opening, and (C) a dye stabilizer which is a compound interacting with the cyclic color-forming compound to stabilize the ring-opened dye body and cause color formati

Abstract: The object of the present invention is to provide a novel developer capable or realizing a thermal recording material superior in preservation stability (i.e., heat resistance, moisture resistance) of color images and non-image areas, while satisfying the recent request for high sensitivity, and a thermal recording material using the developer.

Abstract: An image display medium that includes a photoconductive layer containing a photochromic compound and an electron accepting compound; and a substrate, in which the photochromic compound contains a fulgide compound, and the electron accepting compound contains a compound selected at least from: a) a phosphonic acid compound having an aliphatic group containing 12 or more carbon atoms; b) an aliphatic carboxylic acid compound having an aliphatic group containing 12 or more carbon atoms; and c) a phenolic compound having an aliphatic group containing 12 or more carbon atoms, a process for forming an image using the medium, and a multicolor image-forming apparatus using the medium and suitable for the process.

Abstract: A simplified method of manufacturing a color-converting filter is disclosed which permits highly detailed patterning. Color filter layers are formed on a transparent substrate, a colorant layer containing a color-converting colorant is formed on the color filter layers, and the colorant layer is exposed via the transparent substrate and the color filter layers using colorant-decomposing light. Color-converting layers are formed in positions corresponding to the color filter layers. The color-converting colorant is decomposed by light outside the wavelength region transmitted by the color filter layers. The colorant-decomposing light contains a wavelength component that decomposes the color-converting colorant, and the color-converting layers emit, through wavelength distribution conversion, light that will be transmitted by the color filter layers.

Abstract: An element for forming a print-out image containing a substrate, which may be cellulose, having a first surface and a second surface; a dye forming composition on the first surface of the substrate; and a non-dye forming composition on the second surface of the substrate having at least one hydrogen donor compound.

Abstract: The present invention relates to an optical memory device and an operating process thereof. The optical memory device have a recording layer containing a photochromic compound and an electron-accepting compound which is a Lewis acid compound having a Lewis acid part and a long chain part having carbon atoms of C12 or more. One aspect of the operating process has a recording step which recording is performed on the optical memory device by irradiating visible light corresponding to the absorption band of the colored photochromic compound for recording using decolorizing, before and after recording, heating treatments are performed to control the decolorizing sensitivity of the photochromic compound, and an erasing step which ultraviolet light is irradiated to the area including the recorded portion in order to uniformly color the recording layer again.

Abstract: A multilayer imageable article with at least two layers including a multiphoton imgeable composition. The composition includes a multiphoton-sensitive photoactive system and at least one of a dye and a dye precursor. The photoactive system includes a multiphoton sensitizer capable of simultaneously absorbing at least two photons, an electron acceptor capable of transformation to a dye-activating species upon interaction with the multiphoton sensitizer subsequent to absorption of at least two photons, and optionally an electron donor.

Abstract: A method and apparatus for producing identification (ID) cards using a photosensitive imaging system employing microcapsules is described. In accordance with one aspect of the invention, ID cards are produced by translating an image containing identifying indicia into a latent image on an appropriate photosensitive donor sheet, pressure developing the latent image, forming a full color print of the image on a developer sheet, laminating an ID card substrate in registration with the image to the developer sheet and die cutting the laminated article to produce an ID card. Self-contained imaging systems can also be used to produce identification cards. The image preferably includes unique information useful in identifying the card holder such as a photograph, fingerprint, signature, description, name, etc. The identifying indicia may be combined with non-variable information including background printing, card issuer data, logos, security features, etc.

Abstract: An element for forming a print-out image containing a substrate, which may be cellulose, having a first surface and a second surface; a dye forming composition on the first surface of the substrate; and a non-dye forming composition on the second surface of the substrate having at least one hydrogen donor compound.

Abstract: The coating quality of an adhesive layer applied in direct contact on a polyester film is improved by using an alkyl (poly)glycoside as surfactant. A polyester film carrying such layer is suitable as support for a photosensitive material.

Abstract: The present invention related to an azomethine dye precursor represented by the following general formula (1) and the image-forming material and image-forming method using the azomethine dye precursor: wherein Ar represents an aryl group or a heterocyclic group which may each have a substituent; X represents a bivalent group linking a carbon atom and a nitrogen atom; and Cp represent a coupler residue which may or may not form a ring.

Abstract: The present invention is concerned with photopolymer materials sensitive to infrared, near infrared, red and green light radiation for initiating polymerization and to applications of such photopolymer, like holographic polymer dispersed liquid crystal (H-PDLC) or reversible dye doped photopolymer (RDDP) materials, for making optical devices. The invention relates to holographic polymer dispersed liquid crystal and reversible dye materials having improved electrical and optical switching properties.

Abstract: The present invention related to an azomethine dye precursor represented by the following general formula (1) and the image-forming material and image-forming method using the azomethine dye precursor: wherein Ar represents an aryl group or a heterocyclic group which may each have a substituent; X represents a bivalent group linking a carbon atom and a nitrogen atom; and Cp represent a coupler residue which may or may not form a ring.

Abstract: A printing method directed to a plurality of pieces of slip paper which have been bound into a book and to the outer surface, of which ink containing an initiator and either one of coloring matter and a precursor of coloring matter is applied are placed. A printing plate has a through portion through which radiation penetrates and whose shape corresponds to a pattern to be printed. The printing plate is placed ont he stacked slip paper and X-rays are irradiated upon the printing plate fro the above direction so as to print the pattern of a character on each pieces of the slip paper at a desired are thereof.

Abstract: Novel compositions for making structured color images and application thereof Compositions for making structured color images comprising (a) a soluble pigment precursor which can be transformed to an insoluble pigment by means of chemical, thermal, photolytic or radiation-induced method, and (b) a binder polymer or prepolymer, or a positive or negative resist-type resin which can be structured by crosslinking, polymerization or depolymerization by applying heat or electromagnetic irradiation. The compositions can be applied to optical and thermal recording, printing, and the production of color filters for Liquid Crystal Displays, with high accuracy, high transparency and high stability.

Abstract: A printing method directed to a plurality of pieces of slip paper which have been bound into a book and to the outer surface, of which ink containing an initiator and either one of coloring matter and a precursor of coloring matter is applied are placed. A printing plate has a through portion through which radiation penetrates and whose shape corresponds to a pattern to be printed. The printing plate is placed ont he stacked slip paper and X-rays are irradiated upon the printing plate fro the above direction so as to print the pattern of a character on each pieces of the slip paper at a desired are thereof.

Abstract: A method for controlling the intensity of an imaging laser of an electrophotographic device in order to produce both positive and negative output. This is accomplished by using a software controlled digital circuit to increase or decrease the power supplied to the laser based on the user's desire to print positive or negative output. When the user desires to print positive output, the laser is set to full power. When the user selects negative mode printing, the power to the laser is digitally reduced by a factor unique to the electrophotographic characteristics of the printing device.

Abstract: Process for forming a selectively colored polymeric layer, or a three-dimensional article made of polymeric layers, wherein a photocurable, photocolorable composition is irradiated with a low dose of light to cure and a different, preferably higher, dose of light to color. The process is particularly useful for preparing selectively colored ornamental and industrial articles and models of plant and animal parts, especially medical models.

Abstract: A photo-decoloring dye represented by the following Formula (1), ##STR1## wherein Z.sub.1, Z.sub.2 and Z.sub.3 each represents a carbon atom or a nitrogen atom, R.sub.1, R.sub.2 and R.sub.3 each represents a hydrogen atom and substituents, Z.sub.2 and Z.sub.3 may form a condensed ring, Z represents N or CH, X+ represents an organic cation, m represents an integer of 0 to 4, n represents an integer of 0 to 3.

Abstract: Applications of photoerasable colorant composition include photoerasable price markings for pricing goods, documents such as gaming tickets for securely communicating concealed information, photoerasable paint for temporary markings on terrain and structures such as signs, roadways, trees, and buildings, marking instruments such as pens, and wick or felt markers, ultraviolet light exposure indicators, and dry printing. The photoerasable or mutable colorant composition comprises a mutable colorant and an ultraviolet radiation transorber which, upon irradiation with ultraviolet radiation, interacts with the colorant to irreversibly mutate the colorant and thereby render the colorant substantially colorless. The mutable colorant composition may also include a molecular includant.

Abstract: Compositions for making structured color images comprising(a) a soluble pigment precursor which can be transformed to an insoluble pigment by means of chemical, thermal, photolytic or radiation-induced method, and(b) a binder polymer or prepolymer, or a positive or negative resist-type resin which can be structured by crosslinking, polymerization or depolymerization by applying heat or electromagnetic irradiation.The compositions can be applied to optical and thermal recording, printing, and the production of color filters for Liquid Crystal Displays, with high accuracy, high transparency and high stability.

Abstract: Thermochromic materials are incorporated into constructions that facilitate accurate reproductions of monochrome or full-color images having multiple gray levels. The invention utilizes thermochromic materials having different transition temperatures to facilitate their selective activation. The materials may be located in a single layer of a recording sheet, or in multiple layers. The invention also comprises thermal printing apparatus useful in imaging the foregoing constructions, particularly those exhibiting hysteresis.

Abstract: Disclosed is a novel positive-working or negative-working chemical-sensitization photoresist composition useful in the photolithographic patterning works for the manufacture of electronic devices. The photoresist composition is characterized by a unique acid-generating agent capable of releasing an acid by the pattern-wise exposure of the resist layer to actinic rays so as to increase or decrease the solubility of the resist layer in an aqueous alkaline developer solution. The acid-generating agent proposed is a novel cyano group-containing oxime sulfonate di- or triester compound represented by the general formulaA[C(CN).dbd.N--O--SO.sub.2 --R].sub.n,in which each R is, independently from the others, an unsubstituted or substituted monovalent hydrocarbon group such as alkyl groups, A is a divalent or tervalent organic group or, preferably, phenylene group and the subscript n is 2, when A is a divalent group, or 3, when A is a tervalent group or, preferably 2.

Abstract: Disclosed is a novel positive-working or negative-working chemical-sensitization photoresist composition useful in the photolithographic patterning works for the manufacture of electronic devices. The photoresist composition is characterized by a unique acid-generating agent capable of releasing an acid by the pattern-wise exposure of the resist layer to actinic rays so as to increase or decrease the solubility of the resist layer in an aqueous alkaline developer solution. The acid-generating agent proposed is a novel cyano group-containing oxime sulfonate di- or triester compound represented by the general formulaA[C(CN).dbd.N--O--SO.sub.2 --R].sub.n,in which each R is, independently from the others, an unsubstituted or substituted monovalent hydrocarbon group such as alkyl groups, A is a divalent or tervalent organic group or, preferably, phenylene group and the subscript n is 2, when A is a divalent group, or 3, when A is a tervalent group or, preferably 2.

Abstract: The sensitivity to radiation of combinations of cationic electron acceptors (such as phosphonium, sulfonium, diazonium and iodonium salts) with sensitizing dyes, which sensitize these cationic electron acceptors to wavelengths (typically visible wavelengths) to which they are not sensitive in the absence of the dye, can be increased by including with the cationic electron acceptor and the sensitizing dye a supersensitizer which has an oxidation potential lower than that of the sensitizing dye, the supersensitizer being an ionic compound having a cation comprising an ionic grouping, said grouping comprising at least one atom of an element from Group VB, VIB or VIIB of the Periodic Table.

Abstract: A thermal recording element comprising a support having thereon a dye layer comprising a polymeric binder containing:(a) a metallized complex of a formazan dye that absorbs at from about 400 to about 850 nm; and(b) an organic carboxylic acid;the dye layer having associated therewith:(c) a hexaarylbiimidazole which is an oxidative dimer of a 2,4,5-triarylimidazole having one of the following formulas: ##STR1## wherein: R, R.sup.1 and R.sup.2 each independently represents hydrogen, a substituted or unsubstituted alkyl or alkoxy group of from 1 to about 12 carbon atoms, amino, a substituted or unsubstituted cycloalkyl group having from about 5 to about 7 carbon atoms, or an electron-rich heterocyclic group having from about 5 to about 7 atoms, with the proviso that at least one of R and R.sup.1 is the alkoxy or amino group;X and X.sup.1 each independently represents oxy or imino;Z is an alkylene group of 1 or 2 carbon atoms; andm, n and o each independently represents an integer of 0 to 5.

Abstract: A thermal recording element comprising a support having thereon a dye layer comprising a polymeric binder containing:(a) a formazan dye that absorbs at from about 400 to about 850 nm, and(b) a hexaarylbiimidazole which is an oxidative dimer of a 2,4,5-triarylimidazole having one of the following formulas: ##STR1##

Abstract: Positive-acting no-process printing plates are disclosed in which a stable visual or print-out image is obtained upon exposure of the plate to actinic radiation. The visual image is obtained by incorporation into the photosensitive layer, a dye which is irreversibly bleached upon exposure of the printing plate. For example, an acid which is generated upon exposure of a photopolymer to radiation may be used to bleach a dye of this invention. The visual or print-out images produced are useful in the production cycle and are stable to basic environments that may be encountered in the production setting.

Abstract: A thermal transfer recording material capable of giving a color image having an excellent color reproducibility as well as good light fastness and free from fading, bleeding and contamination of an article contacted is provided. The thermal transfer recording material comprises a thermal transfer dye donating material containing the specified thermally migratable, dissociative heteryl azo dye of phenol or naphthol type and an image receiving material for thermal transfer printing, containing at least one of basic materials and mordants as a dye receiving compound.

Abstract: A bleachable composition, including an acid photogenerator and a near-infrared radiation-absorbing dye or pigment, is utilized in a method of migration imaging to prevent unwanted absorptions. This composition can be incorporated either in the thermoplastic imaging surface layer of the imaging element, in the marking particles applied to the element, or both. Alternatively, the components of the bleachable composition can be separated with one in the thermoplastic imaging surface layer and the other in the marking particles. After the imaging element is marked and exposed with near-infrared radiation, the bleachable composition caused exposed portions of the imaging element to be bleached. If further bleaching is needed, the element can subsequently be exposed with near-ultraviolet radiation. A migration imaging method, which does not employ the bleachable composition of the present invention, wherein marking particles are magnetically attracted to the imaging element, is also provided.

Abstract: Disclosed is a magnetic recording element comprising a support having coated on at least one major surface thereof a layer of a magnetic recording medium and a photosensitive layer which may be separate from or integral with the magnetic recording layer and which contains an infrared absorbing dye or its precursors. Information can be imparted to the photosensitive layer by imagewise exposure to actinic radiation which will either promote or inhibit generation or destruction of the infrared absorbing dye.

Abstract: A process of forming a single color, dye ablation image having an improved D-min comprising imagewise heating by means of a laser, a dye-ablative recording element comprising a support having thereon a dye layer comprising an image dye dispersed in a polymeric binder and an infrared-absorbing material, the laser exposure taking place through the dye side of the element, and removing the ablated image dye material to obtain an image in the dye-ablative recording element, and wherein the element contains an interlayer containing infrared-absorbing material and which is located between the support and the dye layer.

Abstract: The present invention provides a recording material utilizing a reaction between a colorless or light-colored dye precursor and a color developer capable of forming a color upon coming into contact with the dye precursor, the recording material being characterized in that the material comprises at least one compound serving as the dye precursor and represented by the formula (1), and an acidic substance serving as the color developer ##STR1## wherein R.sub.1 to R.sub.6, p and q are defined in the specification. At least one selected from the group consisting of phenolic compounds of the formulae (10), (11) and (12) and phenolic resin having a partial structure of the formula (13) can be used, as required, to further improve the color forming properties and change the color of recorded images from reddish purple or purple to blue or dark blue.

Abstract: An information recording medium comprises a recording layer including a mixture of organic polysilane and oxo metallic phthalocyanine pigment. Information is recorded by adding heat or light to the recording layer. In a method for recording information onto the information recording medium, a decoloring reaction of oxo metallic phthalocyanine pigment is used which is caused by heating the recording layer to a temperature equal to or higher than a pyrolyzing point of organic polysilane.

Abstract: A thermal-dye-bleach construction comprising a thermal nucleophile-generating agent in association with a styryl dye having a nucleus of general formula (I): ##STR1## representing the nucleus of a styryl dye in which R=methyl or ethyl groupY=alkoxy of 1 to 20 carbon atomsm=1 or 2,n=1, 2, or 3, andx.sup..crclbar. =an anionThe aromatic fused benzene portion of the indolenine ring may be further substituted with commonly acceptable dye substituents such as alkyl and substituted alkyl (of 1 to 10 carbon atoms) groups, alkoxy groups (preferably of 1 to 10 carbon atoms), fused aromatic rings (as to make the benzene ring a fused naphthalene ring), halogen (including fluoro), cyano, nitro, carboxamido, amido, etc. One or two substituents chosen variously from said group may also be present on the phenyl ring to which the alkoxy group is attached.

Abstract: Method for fabricating components for integrated optics are provided wherein a film of polystyrene doped with methyl red (PS-MR) on a glass substrate, is masked, e.g. with one or more metallic strips on a glass plate and such film is irradiated with, e.g. a UV lamp, tuned within the absorption band of such film, in air, to photobleach the film portions around channels covered by the masking strips and reduce the refractive index thereof below that of the unbleached film channels. The bleached film portions then provide reflective beam confining interfaces which define the unbleached channels and form waveguides within the film. The invention also provides for interfering two laser beams of like .lambda., at a coupling spot on the film, which beams are again tuned within the absorption band of such film, which bleach alternate lines or bars of such film to provide a phase grating therein.

Abstract: A pattern forming method, comprising the steps of providing a resist film on a substrate; providing a photosensitive film containing a photosensitive diazonium salt on the resist film; and then subjecting the resultant composite to pattern exposure by use of a light to which both of the resist film and the photosensitive diazonium salt are sensitive, can employ a composition for pattern formation which comprises a photosensitive diazonium salt, a resin binder and a solvent. By this method, a minute pattern of 1 .mu.m or less can be formed, utilizing effectively the UV-ray exposure technique of the prior art, with good dimensional precision and stability.

Abstract: A radiation responsive composition containing a compound represented by the following formula (I) and a photoreducing agent capable of forming a redox couple together with said compound for many uses, e.g., image formation, etching, plating, etc.: ##STR1## wherein N represents a nitrogen atom; X represents an oxygen atom (--O--), a sulfur atom (--S--), or a nitrogen-containing group of formula, ##STR2## R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represents a mere bond, a substituted or unsubstituted alkyl, aryl, heterocyclic, acyl, aralkyl, alkenyl, alkynyl or carbamoyl group, or a sulfonyl group into which a substituted or unsubstituted alkyl or aryl group has been introduced, provided that at least one of the substituents R.sup.1 to R.sup.3 be a substituted or unsubstituted aryl or heterocyclic group and that two or more of R.sup.1, R.sup.2 and R.sup.3, or of R.sup.1, R.sup.2, R.sup.3 and R.sup.

Abstract: A silver halide photosensitive material comprising a support having thereon a layer containing (a) an organic compound which releases a free radical on contact with light rays and (b) a compound which undergoes a change in the absorption spectrum due to the action of the released free radical.

Abstract: A photographic contact printing process is disclosed having application in the mass production of replicate video discs from a master disc, and other applications wherein it is desired to replicate micro-detail over a relatively large area. A problem with conventional contact printing from a mask to a photographic medium is one of maintaining intimate contact over a relatively large area since dust, dirt, etc., are almost impossible to completely eliminate in any practical manner. In accordance with the present invention, a contact printing process is provided wherein intimate contact is not necessary for making high quality contact prints. The present invention recognizes that in contact printing information from a master disc to a replicate disc, the contact printing process is significantly less sensitive to imperfect contact between the master disc and the replicate disc if one employs a replicate disc comprising a photosensitive material having a certain optical properties.