Co-irradiation method for producing positive images utilizing phototropic spiropyran or indenone oxide or dual response photosensitive composition

Abstract

Abstract METHOD FOR PRODUCING POSITIVE IMAGES BY IRRADIATING PHOTOSENSITIVE COMPOSITIONS WHICH ARE CHARACTERIZED BY FORMING COLOR ON IRRADIATION WITH LIGH IN A FIRST WAVELENGTH RANGE AND BY BEING PREVENTED FROM FORMING COLOR ON IRRADIATION WITH LIGHT IN A DIFFERENT SECOND WAVELENGTH RANGE. THE METHOD COMPRISES SIMULTANEOUSLY EXPOSING SUCH COMPOSITION DISPOSED AS AN IMAGE-CAPTURE SURFACE TO RADIATIONS IN BOTH WAVELENGTH RANGES, WITH (1) THE COLOR-PREVENTING RADIATION BEING APPLIED PATTERN-WISE ACCORDING TO THE DESIRED IMAGE TO BE CAPTURED, (2) THE COLOR-FORMING RADIATION BEING APPLIED OVER THE ENTIRE SURFACE TO BE IMAGED, AND (3) THE INTENSITIES AND THE RELATIVE INTENSITIES OF THE TWO RADIATIONS BEING SUCH THAT (I) THE COLOR-PREVENTING RADIATION IS ITSELF EFFECTIVE FOR COLOR-PREVENTING AND (II) THE COLOR-FORMING RADIATION IS ITSELF EFFECTIVE TO CAUSE COLOR FORMATION IN OTHER THAN THE CO-STRUCK AREAS BUT IS INEFFECTIVE IN THE PRESENCE OF THE COLOR-PREVENTING RADIATION IN THE CO-STRUCK AREAS TO CAUSE SUBSTANTIAL COLOR FORMATION. A PREFERRED COMPOSITION FOR USE WITH THIS METHOD IS A MIXTURE OR (A) COLOR FORMING COMPONENTS WHICH ARE RESPONSIVE TO SAID FIRST WAVELENGTH RANGE AND THEREBY PRODUCE A FIRST PHOTO-INDUCED OXIDATION-REDUCTION REACTION, AND (B) DEACTIVATING COMPONENTS WHICH ARE RESPONSIVE TO SAID SECOND WAVELENGTH RANGE AND THEREBY PRODUCE A DEACTIVATING AGENT BY A SECOND OXIDATION-REDUCTION REACTION, SAID DEACTIVATING AGENT THUS PRODUCED BEING A STRONGER REDUCING AGENT THAN THE REDUCTANT MEMBER OF THE COLOR-FORMING COMPONENTS AND THEREBY PREVENTING THE COLOR-FORMING REACTION WHEN THE COMPOSITION IS SUBSEQUENTLY EXPOSED TO THE FIRST WAVELENGTH RANGE. ANOTHER USEFUL PHOTOIMAGEABLE SYSTEM INCLUDED PHOTOCHROMIC COMPOUNDS, E.G., THE SPIROPYRANS, WHICH FORM COLOR ON BEING EXPOSED TO LIGHT OF ONE WAVELENGTH RANGE AND WHICH REVERT TO THE ORIGINAL COLOR ON BEING EXPOSED TO LIGHT OF A SECOND WAVELENGTH.

Inventors

• 👤 Rolf Dessauer

Bibliographic Details