Abstract: A method of preparing a fine pattern on a substrate characterized by the dry development of a photoimaged, etch resistant pattern on a receiver substrate. The pattern is transferred from a carrier substrate to the receiver substrate via a hardenable liquid adhesive. This method eliminates adverse reflection effects caused from substrate topography in single layer photoresist systems and also avoids time consuming multiple coatings in multilayer photoresist systems used to make fine patterns. The method is particularly useful in the fabrication of integrated circuits and fine dimension patterns.

Abstract: A white, partially translucent, metallized film article which having a flexible, heat resistant, polymeric film material with opposite sides. The film material has deposited on a first side a metal coating which is spectrally reflective and partially light transmissive in the visible region of the spectrum, is capable of transmitting from about 1% to about 70% of incident visible light cast thereon; the second side having a white outermost surface, and has a visible light opacity of from about 0.5 to about 0.98.

Abstract: A method of preparing a fine pattern on a substrate characterized by the dry development of a photoimaged, etch resistant pattern on a receiver substrate. The pattern is transferred from a carrier substrate to the receiver substrate via a hardenable liquid adhesive. This method eliminates adverse reflection effects caused from substrate topography in single layer photoresist systems and also avoids time consuming multiple coatings in multilayer photoresist systems used to make fine patterns. The method is particularly useful in the fabrication of integrated circuits and fine dimension patterns.

Abstract: A manufacturing process to produce a controllable integral membrane (28) in sheet-like photosensitive laminates (20), said photosensitive laminate being adapted to adhere to the surface to be etched (36). By the use of the present invention the revealed image (33) washes out without detail roots leaving the substrate (22), transfers easily, even if it is very fine, and can be etched on said surface to be etched very nicely.

Abstract: A process for producing color filters which enable a transparent electrode for forming a coloring matter film to be used as a transparent electrode for driving liquid crystals, and a resist for a light-shielding film used in this process for forming an insulating black matrix, is disclosed. The above production method comprises forming a black matrix over electrodes other than those corresponding to the individual separated colors and, at the same time, insulating layers as electrode contact window belts by utilizing the black matrix material; forming the electrode contact window belts by forming an electrically conductive layer over the black matrix so that they connect within each electrode contact window belt unit, but do not connect with those in different electrode contact window belt units; and forming a coloring matter layer by a micellar disruption method.

Abstract: A thermal transfer image receiving material and a method for preparing therefrom a proof for printing are disclosed. The material comprises a support and provided thereon, a peelable layer and a first image receiving layer in this order, and the method comprises the steps of;contacting a thermal transfer layer onto the thermal transfer image receiving material,imagewise exposing the contacted materials to light,transferring the exposed portions of the transfer layer to the first image receiving layer, said transferring comprising transferring of at least yellow, magenta, and cyan color images on the first image receiving layer to form a color image, andtransferring the formed color image to a second image receiving layer.

Abstract: A laminar thermal imaging medium, and a method of preparing same, are disclosed and include a photohardenable adhesive layer containing a photopolymerizable ethythenically unsaturated monomer, and a barrier layer for providing resistance to the diffusion of the polymerizable monomer therethrough to other layers of the thermal imaging medium. The barrier layer increases substantially the time period before which photohardening of the adhesive layer need be performed, during which time cutting and other manufacturing operations can be performed. The elastic and non-brittle character of the barrier layer provides improved durability of images prepared from the thermal imaging medium.

Abstract: A negative-working radiation-sensitive mixture containinga) a compound which generates a strong acid under the action of actinic radiation,b) a compound having at least two groups crosslinkable by means of acid andc) a polymeric binder which is insoluble in water and soluble or at least swellable in aqueous alkaline solutions,wherein the compound (a) contains a 2,4,6-tris-(2-hydroxyethoxy)-[1,3,5]triazine which is esterified with two or three arylsulfonic acids or heteroarylsulfonic acids, is distinguished by high resolution and high sensitivity over a wide spectral range. It also shows high thermal stability and does not form any corrosive photolysis products on exposure. A radiation-sensitive recording material which has been produced with this mixture is suitable for the production of photoresists, electronic components, printed plates or for chemical milling.

Abstract: The present invention relates to a process for preparing a multicolored proof, using a radiation-sensitive recording material which comprises a temporary, sheet-shaped layer support, a thermally transferable layer containing a colorant in one primary color and a radiation-sensitive layer. The process comprises the steps of: a) exposing the recording material imagewise b)developing the exposed layer with an aqueous-alkaline solution to uncover the thermally transferable image areas, and c) contacting the coated side of the recording material with an image receptor and transferring the transferable image areas to the image receptor, with the application of heat and pressure, to produce a partial image in the first primary color. The above-described process steps are repeated at least once, using a radiation-sensitive recording material which contains a colorant in another primary color in its thermally transferable layer.

Abstract: This invention provides an improved negative-working or positive-working, single sheet color proofing method which can accurately reproduce images by using colored, photosensitive layers on substrates which are then overcoated with partially developable adhesive layers. The final construction is useful in predicting the image quality from a lithographic printing process. The partial removal of the adhesive layers cleans out any background stain which may remain from the incomplete removal of the photosensitive layer.

Abstract: A peel-off developable pattern sheet comprising a transparent flexible substrate having thereon a pattern comprising a photopolymerizable color image-forming material layer and a process for producing a monochromatic or multi-color patterned display element by making use of the pattern sheet(s) are disclosed. A patterned display element can be produced in a continuous manner in an organic solvent-free working environment. The formed pattern has excellent sharpness and well-controlled surface properties.

Abstract: There is disclosed a laminar thermal imaging medium comprising a pair of sheet members and at least a layer of image-forming substance confined therebetween in laminar relation thereto, said laminar thermal imaging medium being actuatable in response to intense image-forming radiation for production of an image in said image-forming substance, said medium material having a tendency toward stress-induced adhesive failure at the interface therein having the weakest adhesivity, and such tendency being reduced by a polymeric stress-absorbing layer in close proximity to said interface, said polymeric stress-absorbing layer being capable of absorbing physical stresses applied to said laminar thermal imaging medium.

Abstract: A dry film for forming a solder mask includes a cover sheet, a photoimageable composition layer which is curable to form a solder mask and a top coat interposed between the cover sheet and the photoimageable composition layer which is selectively adherent to the photoimageable composition layer. The dry film is applied to a surface of a printed circuit board. With heat, vacuum and mechanical pressure, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, partially conforming the photoimageable composition layer to the contours thereof. Within about 60 seconds and with the photoimageable composition layer still heated, the cover sheet is peeled away, leaving the top coat as a protective covering over the photoimageable composition layer. Removal of the cover sheet allows the photoimageable composition layer to fully conform to the contours of the printed circuit board. Immediately thereafter, the circuit board is cooled to about ambient temperature or below.

Abstract: An optical or magneto-optical recording card is produced using a transfer type optical or magneto-optical recording medium. The transfer type optical or magneto-optical recording medium comprises a base film, a peeling layer, an optical or magneto-optical recording layer and a light permeable adhesive layer which are successively superimposed one above another to constitute a layered structure. A protective layer is adhered to the transfer type optical or magneto-optical recording medium with the aid of an adhesive layer and the base film is then peeled off together with the peeling layer. Next, the protective layer to which the optical or magneto-optical recording layer is adhered is adhesively attached to a card base in such a manner that the optical or magneto-optical recording layer is interposed therebetween whereby an optical or magneto-optical recording card is completely produced. The transfer type recording medium can be preserved in such a state that it is wound about a reel.

Abstract: There is disclosed a thermal imaging laminar medium, actuatable in response to intense image-forming radiation for production of an image, and including a thermoplastic intermediate layer which, upon separation of the sheet-like or web materials of the laminar medium after thermal exposure, provides surface protection for one of the pair of images obtained thereby.

Abstract: A method of producing a polychromatic colored image with clear fine patterns, comprising the steps of:(a) contacting a light-sensitive colored resin layer, provided on a temporary support transmissive of ultraviolet rays with an adhesive layer provided on a permanent support;(b) imagewise exposing the light-sensitive colored resin layer to a pattern through the temporary support;(c) peeling the temporary support from the imagewise exposed resin layer;(d) developing the imagewise exposed colored resin layer to form a colored resin pattern on the adhesive layer;(e) embedding the colored resin pattern into the surface of the adhesive layer by applying pressure through a material having a surface energy lower than that of both the colored resin pattern and the adhesive layer;(f) contacting a light-sensitive resin layer of another image-forming material colored in a tint different from resin layers previously formed on the adhesive layer with the adhesive layer; and(g) repeating the exposure, development and embed

Abstract: An optical recording card is produced using a transfer type optical recording medium. The transfer type optical recording medium comprises a base film, a peeling layer, an optical recording layer and a light permeable adhesive layer which are successively superimposed one above another to constitute a layered structure. A protective layer is adhered to the transfer type optical recording medium with the aid of an adhesive layer and the base film is then peeled off together with the peeling layer. Next, the protective layer to which the optical recording layer is adhered is adhesively attached to a card base in such a manner that the optical recording layer is interposed therebetween whereby an optical recording card is completely produced. The transfer type recording medium can be preserved in such a state that it is wound about a reel. Accordingly, the transfer type recording medium is adhered to the protective layer when the optical recording card is produced, and thereafter it is adhered to the card base.

Abstract: The invention provides a method for protecting an image which comprises providing a multilayered colored image on a permanent receiver which may be any of a wide range of materials. A photosensitive element on a substrate is laminated to a temporary element and exposed with substrate removal before development. After development, the steps are repeated with another color. A protective element is laminated to the colored image. After removal of the support of the temporary element, the colored image with protective element is laminated to a permanent receiver.

Abstract: A display such as meter panel and advertising display comprises a color image forming layer provided on a light-transmitting permanent support via a photo-polymerizable adhesive layer, and a photo-polymerizable image-receiving layer closely adhered to the color image forming layer. The display can be effectively produced by a process comprising the steps of forming a color image on a photo-polymerizable image-receiving layer of a photosensitive image-receiving material, placing it upon a photo-polymerizable adhesive layer formed on a light-transmitting permanent support to form a laminate so that the photo-polymerizable image-receiving layer and the photo-polymerizable adhesive layer face each other and then exposing the laminate to light so as to closely adhere the photo-polymerizable image-receiving layer and the photo-polymerizable adhesive layer to their adjacent layers, respectively, by the photo-polymerization.

Abstract: Sheet material including a cellulose acetate temporary support carrying thereon a continuous strippable layer. The strippable layer is a non-photosensitive layer containing a coverage of at most 20 g/m.sup.2 gelatin hardened to a degree corresponding to the addition of at least 0.001 g of formaldehyde per g of gelatin. Transfer of the strippable layer from the temporary support onto an image material having e.g. an imaged hydrophilic colloid layer or relief pattern given improved gloss control and optical dot gain control for such image material.

Abstract: Multicolor image products useful for prepress color proofing. The products are laminates of a transfer support sheet; an adhesive layer of a heat-fusible and bondable material on a surface of said transfer support sheet; an image layer of a first color provided on the adhesive layer and having image areas of a water-insoluble resin component and non-image areas, the image areas being bonded to the surface of the adhesive layer; and one, two or three additional image layers each of a different color other than that of the first image layer.

Abstract: A method for coating a printing screen with a sealer to avoid pinholing and damage to the screen from extended use. The method includes coating the inside of the screen with a photo emulsion, exposing the emulsion to the image to be printed, and etching out the exposed screen. Next, applying to the outside surface of the etched out screen a sheet of easy removable pressure sensitive vinyl, and next treating the etched out screen with a sealing composition, which provides a protective barrier for that part of the screen that prevents ink from printing. The sealing composition is advantageously a two part epoxy resin or an air-moisture curing urethane polymer.

Abstract: This invention relates to a peel-apart photosensitive element comprising a strippable coversheet, a photorelease layer, a photohardenable layer, an elastomeric layer, and a support, which is useful in a variety of image reproduction processes.

Abstract: The invention provides a photographic article having a protected image which comprisesa) a colored image disposed on a substrate; andb) a thin, transparent, colorless, thermoplastic adhesive composition directly on the surface of the image, wherein said adhesive is substantially non-tacky at room temperature, and comprises one or more thermoplastic polymers of copolymers capable of forming a flexible film, said adhesive being capable of being transferred directly to the image when the adhesive is first disposed on the release surface of a temporary support and said image and adhesive are laminated together under pressure at temperatures of between about 60.degree. C. and about 90.degree. C. and said temporary support is peeled away; andc) a non-self supporting antiblocking layer directly on said adhesive said antiblocking layer being transparent, colorless and comprises one or more organic polymers or copolymers, which coating does not cohesively block at about 50.degree. C. or less.

Abstract: A dry film for forming a solder mask includes a cover sheet, a photoimageable composition layer which is curable to form a solder mask and a top coat interposed between the cover sheet and the photoimageable composition layer which is selectively adherent to the photoimageable composition layer. The dry film is applied to a surface of a printed circuit board with a minor portion of the area of the photoimageable composition layer tacked to the printed circuit board. The cover sheet is peeled away. With heat and vacuum, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, conforming the photoimageable composition layer to the contours thereof and leaving the top coat as a protective covering over the photoimageable composition layer. The photoimageable composition layer is exposed to patterned actinic radiation, developed and cured to form a hard, permanent solder mask.

Abstract: A process for manufacturing a hologram on a stable substrate, such as flat glass, and for thereafter transferring that hologram to another substrate, including a curved surface. The process includes the use of an intermediate polyene-based urethane or epoxy acrylate adhesive layer, preferably comprised of Norland Optical Cement. An improved hologram is also disclosed having superior moisture barrier properties.

Abstract: This invention relates to an image reproduction process, more particularly a color proofing process, which utilizes a peel-apart photosensitive element comprising a strippable coversheet, a photohardenable layer, an elastomeric layer, and a support, to produce a positive image of the transparency on the coversheet and a negative image of the transparency on the elastomeric layer.

Abstract: There is disclosed an image forming method which comprises forming an image portion by exposing and developing an image forming material having a light-sensitive composition, and transferring only the image portion onto an image receiving material with the non-image portion of the image receiving material being exposed, wherein the light-sensitive composition contains:(1) at least one selected from:(a) o-quinonediazide compounds; and(b) compositions containing both of a photoacid generating agent and a compound having at least one bond decomposable with the acid; and(2) a polymeric compound having a structure unit represented by the following formula in the molecular structure:CH.sub.2 --CH(OCOR)--wherein R represents an alkyl group having 1 to 17 carbon atoms.

Abstract: A method is disclosed for making holograms on transparent surfaces. A protective thin substrate 18 is laminated to a temporary support 24 for processing. This procedure protects the delicate thin substrate 18 through the processing steps. Upon completion of the processing steps, the thin substrate 18 is then removed from the temporary support 24. The applied photosensitive material gives the delicate thin substrate 18 added strength. The thin substrate 18 is then laminated to the final surface 26. In one embodiment, the final surface 26 corresponds to a car windshield 34. Playback lamps 36 located in the dashboard 32 illuminate the thin substrate 18 to read the holographic image.

Abstract: Probes are formed on a support in a pattern to engage pads on an integrated circuit chip and leads on a printed circuit board. As a preliminary step, a thin layer of a conductive material may be formed on the support. The probes may then be formed by (a) providing facsimiles of the probes on a disposable member, (b) providing a photoresist on the support, (c) adhering the facsimiles to the support in a relationship providing for an easier removal of the disposable member from the facsimiles than the support, (d) developing the photoresist in the areas not occupied on the support by the facsimiles, (e) removing the disposable member, and then the facsimiles, from the support, (f) forming the probes on the support in the spaces previously occupied by the facsimiles and (g) removing the photoresist from the support.

Abstract: This invention relates to positive working color proofing sheet construction which, upon exposure to an actinic radiation source through a screened image, can accuratley reprouce said image. The construction is useful as a color proofing film which can be employed to accurately predict the image quality from a lithographic printing process. The image is produced by forming a composite of a receiver base, diazo or diazide layer, photopolymerizable layer and cover sheet. Upon imagewise exposure, a positive image appears on the receiver base after dry peel apart development.

Abstract: This invention relates to an improved negative- or positive-working, single sheet color proofing method which can accurately reproduce said images on diverse paper stocks by using a carrier to transfer the processed images to paper receiver bases. The final construction is useful in predicting the image quality from a lithographic printing process.

Abstract: This invention relates to a method for making a dry transfer, photopolymerizable positive-working imaging system which provides a photopolymerizable layer on a support and a colored layer on a substrate. Upon imagewise exposure of the photopolymerizable layer, subsequent lamination of the colored layer to the photopolymerized layer and peel apart, a colored image is produced due to the preferred adhesion of the colored layer to the nonexposed areas of the photopolymerized layer.

Abstract: A photosensitive image receiving sheet material employable for color proofing and color display which comprises a photopolymerizable adhesive layer provided on a support via a releasable organic high-molecular polymer layer.

Abstract: A foam plastic substrate has an image formed on its surface by differential ablation by a laser. A composition is applied to the surface in the shape of the image to be formed and has an ablation rate different to that of the foam substrate. After irradiation of the surface, the image is formed in relief on the surface.

Abstract: The invention relates to negative photosensitized sheet constructions which, upon exposure to an actinic radiation source through a screened image, can accurately reproduce said image. The construction is useful as a color proofing film which can be employed to predict the image quality from a lithographic printing process.

Abstract: Process for controlling the visual appearance of an image present on a permanent support in the form of a hydrophilic colloid layer, layer system or relief pattern by the transfer of a continuous non-photosensitive layer from a temporary support onto said permanent support either before or after said image is formed thereon, which comprise by pre-wetting the permanent support either image-free or with said image already thereon, containing the pre-wetted support with said continuous layer carried on the temporary support, and stripping off the temporary support to leave the continuous layer adhering on the permanent support, said continuous layer being non-photosensitive and contains hardened gelatin, the gelatin being applied at a coverage of at most 20 g/m2 and having a degree of hardening corresponding with that achieved by the addition of at least 0.001 g of formaldehyde per gram of gelatin.

Abstract: This invention relates to a process for preparing a reverse image using a pigmented peel-apart element containing a photoinhibitor. More particularly this invention relates to a process for preparing a negative or reverse surprint proof using peel-apart photosensitive elements comprising a strippable cover sheet; a photoadherent layer containing a colorant and a photoinhibitor compound; a tacky, essentially nonphotosensitive contiguous layer; and a support.

Abstract: This invention relates to water developable, negative working photosensitized sheet constructions which, upon exposure to an actinic radiation source through a screened image, can accurately reproduce said image. The construction is useful as a color proofing film which can be employed to predict the image quality from a lithographic printing process. The invention provides both overlay and transfer type proofing sheets which have good fingerprint resistance.

Abstract: A process for preparing a color display comprising the following steps:(a) preparing an uncolored base plate comprising a base plate, an electroconductive layer formed on said base plate and a photosensitive resin layer formed thereon, said photosensitive resin layer being patterned by exposing to light through a mask and developing it to let a portion of the electroconductive layer to be colored appear,(b) forming a color layer by electrodeposition on the portion of the electroconductive layer to be colored,(c) transferring the color layer onto a transfer plate, and(d) further transferring and fixing the color layer onto a transparent substrate from the transfer plate,wherein if the color display is colored with more than one color, the processes (a) to (d) are repeated for the other colors, but once said uncolored base plate is formed, the processes (b) to (d) are repeated.

Abstract: A photoimaged article having a protected image composed of a colored image on a support; and a thin, transparent, flexible, nonself supporting, protective layer on the surface of the image. The layer is substantially nontacky at room temperature, and has at least a major amount based on the weight of the layer of one or more thermoplastic resins of a vinyl acetal, vinyl chloride, or acrylic polymer or copolymer having a Tg of from about 35.degree. C. to about 110.degree. C. The layer is capable of being adhesively transferred directly to the image when the layer is first applied on the release surface of a temporary support, and the image and protective layer are laminated together under pressure at temperatures of between about 60.degree. C. to about 180.degree. C. with subsequent removal of the temporary support. The side of said layer opposite to the image is free from additional layers. The adhesive layer is one which does no cohesively block at temperatures ofabout 50.degree. or less.

Abstract: This invention relates to positive working photopolymerizable sheet constructions which, upon exposure to an actinic radiation source through a screened image, can accurately reproduce said image. The construction is useful as a color proofing film which can be employed to accurately predict the image quality from a lithographic printing process.

Abstract: Paste-consistency photopolymer is imaged onto printed wiring boards by coating the board overall and positioning the photographic film over the board in register and off-contact. A resilient blade is pressed against the phototool at one end of the board and drawn across the surface, thus forcing the photographic film into intimate contact with the photopolymer and purging all air therebetween. Mounted on the resilient blade aft of leading edge is a shuttered tubular lamp which hardens the photopolymer where the photographic film is clear, so that in a single pass the photographic film is sequentially mated and photopolymer exposed, to produce line widths unmatched by competing dry film systems and at speeds of 0.5 feet per second.

Abstract: A method of etching a surface of an article comprises adhering a negative image bearing film, having a first removable transparent support sheet adhered to an exposure side thereof, to a capillary or second film using a first adhesive. The capillary film has a second removable transparent support sheet adhered to a rear side thereof. A development side of the image bearing film is adhered to a front side of the capillary film opposite the rear side. The first removable transparent support sheet is then removed from the exposure side of the image bearing film and the image bearing and capillary films are sprayed with a solvent which creates a negative image in the capillary film corresponding to the negative image in the negative image bearing film. The two films are thus adhered together and adhered to the second removable transparent support sheet as a mask. The mask is dried and then sprayed with a second adhesive.

Abstract: The improvement of the invention consists in the use of a specific ether compound, e.g., diethyleneglycol monomethyl, monoethyl and monobutyl ethers, dipropyleneglycol monomethyl and monoethyl ethers, triethyleneglycol monomethyl and monoethyl ethers and tripropyleneglycol monomethyl ether, as a rinse solvent for a substrate from which the pattern photoresist layer has been removed with a remover solution in the photolithographic processing of semiconductor devices. The rinse solvent is free from the problems in the toxicity to human body and environment pollution relative to waste disposal as well as the danger of fire. The rinse solvent is versatile to be applicable to both of the negative- and positive-working photoresist compositions. Further advantages are obtained by adding an aliphatic amine compound to the rinse solvent.

Abstract: A stripping composition for removing positive organic photoresist from a substrate, such as a semiconductor wafer, contains a triamine, such as diethylene triamine, and a nonpolar or polar organic solvent, such as N-methyl pyrrolidone. This composition will remove positive photoresist from semiconductor wafers, even after ion implantation into the wafers through the positive photo-resist. The wafers are immersed in the composition, for example, at a temperature of 110.degree. C. for five minutes, in an ultrasonic bath after heavy ion implantation doses through the photoresist, such as 1.times.10.sup.16 ions/cm.sup.2, for complete removal of the photoresist. Prebaking the photoresist at a temperature of between about 150.degree. and 220.degree. C. for a time of from about 15 minutes to about 30 minutes, prior to stripping the positive organic photoresist layer with the triamine, enhances the removal.

Abstract: The subject invention involves reduction of light reflection into a photoresist coating over a reflective substrate by the use of a photoactive compound in a photoresist formulation that is the reaction product of a diazooxide and curcumin.

Abstract: A foamed plastics substrate has an image formed on its surface by differential ablation by a laser. A composition is applied to the surface in the shape of the image to be formed and has an ablation rate different to that of the foam. After irradiation of the surface, the image is formed in relief on the surface.

Abstract: A method is described for forming an image by transferring an image layer formed on a transferable light-sensitive material to an image-receiving sheet, and then further transferring the image to a permanent support, wherein the image-receiving sheet comprises a support, a first layer on the support, said first layer being made of a first organic polymeric substance, and a second layer on the first layer, said second layer being made of a second organic polymeric substance, whereinin peeling apart the image-receiving sheet from the transferable light-sensitive material,P.sub.1, P.sub.2, P.sub.3 >P.sub.4wherein P.sub.1 is an adhesion force between the support and the first layer, P.sub.2 is an adhesion force between the first and second layers, P.sub.3 is an adhesion force between the second layer and the image layer, and P.sub.

Abstract: A sandblast photoresist laminate article of manufacture comprising an adhesive layer, a membrane support layer, and a resist layer can be used in etching the surface of articles with a pattern which can be revealed by the resist layer. The resist laminate is usable in a variety of modes of etching such as exposing the resist with a pattern, developing the pattern, applying the developed resist to the object, and etching the pattern into the object. Further, the resist can be used by applying the unexposed sheet-like resist to an object, exposing the resist with a pattern, developing the pattern and etching the pattern into the object. Lastly, the resist laminate can be used by exposing the resist with a pattern, applying the exposed resist to an object, developing the pattern, and etching the pattern into the object. The resist compositions are typically water developable after exposure with actinic radiation.