Reversal photoconductographic processing

Claim 1

A REVERSAL PHOTOCONDUCTOGRAPHIC PROCESS COMPRISING ILLUMINATING BY AN IMAGE HAVING LIGHT AND DARK AREAS A SUBSTANTIALLY COLORLESS PHOTOCONDUCTIVE LAYER TO PRODUCE AN IMAGEWISE DISTRIBUTION OF VARIATIONS IN CONDUCTIVITY, PASSING D.C. CURRECT SIMILARLY DISTRIBUTED THROUGH THE LAYER IN CONTACT WITH A SUBSTANTIALLY COLORLESS DYE PRECURSOR WHICH FORMS A DYE WHEN THE PH IS RAISED TO A CERTAIN VALUE, THE D.C. CURRENT BEING IN THE DIRECTION AND OF SUFFICIENT QUANTITY TO LOWER THE PH OF THE SUBSTANTIALLY COLORLESS DYE PRECURSOR IN THE LIGHT IMAGE AREAS AT LEAST .1 UNIT LEAVING IT STILL SUBSTANTIALLY COLORLESS, TERMINATING THE IMAGEWISE ILLUMINATING AND THEN UNIFORMLY ILLUMINATING THE PHOTOCONDUCTIVE LAYER AND PASSING A SECOND D.C. CURRENT SUBSTANTIALLY UNIFORMLY DISTRIBUTED THROUGH THE LAYER IN THE OPPOSITE DIRECTION AND OF SUFFICIENT QUANTITY TO RAISE TH PH OF THE DYE PRECURSOR INTHE DARK IMAGE AREAS TO SAID CERTAIN VALUE TO FORM SAID DYE IN SAID DARK IMAGE AREAS WITHOUT RAISING IT TO SUCH VALUE IN THE LIGHT IMAGE AREAS.