公开(公告)号：US3782937A

公开(公告)日：1974-01-01

申请号：US3782937D

申请日：1971-12-01

Applicant: POLAROID CORP

Inventor： ELLIS E ,  MACGREGOR P ,  SIMON M

IPC: G03C5/305 ,  G03C8/48 ,  G03C7/00

CPC classification number: G03C8/48 ,  G03C5/305

Abstract: THIS INVENTION RELATES TO PHOTOGRAPHY, AND MORE PARTICULARLY, IT RELATES TO THE USE OF MIXED PHENOL AND MIXED NAPHTHOL PHTHALEINS AS OPTICAL FILTER AGENTS TO PROTECT A SELECTIVELY EXPOSED PHOTOSENSITIVE MATERIAL FROM POSTEXPOSURE FOGGING IN PHOTOGRAPHIC PROCESS WHERE DEVELOPMENT OF THE PHOTOSENSITIVE MATERIAL IS CONDUCTED IN THE PRESENCE OF EXTRANEOUS INCIDENT LIGHT. THIS CLASS OF INDICATOR DYES COMPRISES 3,3-DISUBSTITUTED PHTHALIDES AND 3,3DISUBSTITUTED NAPHTHALIDES WHEREIN ONE OF THE 3,3 SUBSTITUENTS IS A P-HYDROXYPHENYL OR A P-HYDROXYNAPTHYL RADICAL AND THE OTHER IS A PHENYL RADICAL OTHER THAN PHYDROXYPHENYL. AT A FIRST PH IN ALKALINE SOLUTION THE ABOVE-NOTED DYES HAVE A HIGHLY COLORED, LIGHT-ABSORBING FORM CAPABLE OF ABSORBING RADIATION WITHIN A PREDETERMINED WAVELENGTH RANGE IN THE SHORTER WAVELENGTH REGION OF THE VISIBLE SPECTRUM AND AT A SECOND LESS ALKALINE PH HAVE A COLORLESS FORM THAT AIIS SUBSTANTIALLY NON-LIGHT-ABSORBING IN THE VISIBLE SPECTRUM. BY SELECTING A DYE FROM THIS CLASS WHICH IS IN ITS LIGHT-ABSORBING FORM AT THE PH AT WHICH DEVELOPMENT IS PERFORMED, PROTECTION OF THE EXPOSED PHOTOSENSITIVE MATERIAL FROM RADIATION ACTINIC THERETO IS OFORDED WITHIN THE WAVELENGTH RANGE ABSORBED BY THE DYE AND SUBSEQUENT TO AT LEAST THE INITIAL STAGES OF DEVELEPOMENT, THE DYE MAY BE RENDERED SUBSTANTIALLY COLORLESS BY ADJUSTING THE PH TO PERMIT VIEWING OF THE FINAL IMAGE.