公开(公告)号：US3702244A

公开(公告)日：1972-11-07

申请号：US3702244D

申请日：1971-01-21

Applicant: POLAROID CORP

Inventor： BLOOM STANLEY M ,  BORROR ALAN L ,  HUYFFER PAUL S ,  MACGREGOR PAUL T

IPC: C09B11/08 ,  G03C8/48 ,  G03C7/00 ,  G03C1/40 ,  G03C5/54

CPC classification number: G03C8/48 ,  C09B11/08

Abstract: THIS INVENTION RELATES TO PHOTOGRAPHY, AND MORE PARTICULARLY, IT RELATES TO THE USE OF CERTAIN INDICATOR DYES DERIVED FROM INDOLES AS OPTICAL FILTER AGENTS TO PROTECT A SELECTIVELY EXPOSED PHOTOSENSITIVE MATERIAL FROM POSTEXPOSURE FOGGING IN PHOTOGRAPHIC PROCESSES WHERE DEVELOPMENT OF THE PHOTOSENSITIVE MATERIAL IS CONDUCTED IN THE PRESENCE OF EXTRANEOUS INCIDENT LIGHT. THESE INDICATOR DYES CONTAIN AN INDOLE RADICAL, A SECOND AROMATIC RADICAL AND A RING-CLOSING MOIETY BONDED TO THE AROMATIC RADICAL AND TO THE 2- OR 3-POSITION OF THE INDOLE RADICAL. AT A FIRST PH THEY HAVE A HIGHLY COLORED, LIGHT-ABSORBING FORM CAPABLE OF ABSORBING RADIATION WITHIN A PREDETERMINED WAVELENGTH RANGE IS THE SHORTER WAVELENGTH REGION OF THE VISIBLE SPECTRUM AND AT A SECOND PH HAVE A COLORLESS FORM THAT IS 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 AFFORDED WITHIN THE WAVELENGTH RANGE ABSORBED BY THE DYE AND SUBSEQUENT TO AT LEAST THE INITIAL STAGES OF DEVELOPMENT, THE DYE MAY BE RENDERED SUBSTANTIALLY COLORLESS BY ADJUSTING THE PH TO PERMIT VIEWING OF THE FINAL IMAGE.