United States Patent  [191  [II]  3,935,012  [45]  Jan. 27, 1976  Eian  [ 54]  PHOTOSENSITIVE SHEET MATERIALS  [75]  Inventor:  Gilbert  L.  Eian,  White Bear, Minn.  (73]  Assignee:  Minnesota Mining and  Manufacturing Company,  St.  Paul, Minn.  (22]  Filed:  July 12, 1973  (21]  Appl. No.:  378,526  [52]  U.S. CI ..................... 96/48 R;  96/88; 96/114.1;  428/425  [51]  Int. Cl. 2  ....  G03C 5/24:  G03C 1/00; G03C 1/02  [58]  Field of Search ......  96/48  R,  48  HD,  88, 114.1;  117/36.8, 36.9; 428/425  [ 5 6]  References Cited  UNITED ST ATES PATENTS  3,146,348  3,476,562  3,502,476  8/1964  11/1969  3/1970  Workman .......................... 117 /36.8  Yamada et al... ....................... 96/88  Itano et al.. ......................... 96/90  R  3,533,792  3,544,321  3,617,288  3,640,718  I 0/1970  12/1970  11/1971  2/1972  Petro ...................................... 96/88  Yamada et al... ....................... 96/88  Hartman et al... ...................... 96/88  Smith ............................... 96/48 HD  Primary Examiner-Mary  F. Kelley  Attorney, Agent, or  Firm-Alexander, Sell, Steldt &  DeLaHunt  Photosensitive sheet material, containing an acid› cleavable adduct of an image-forming first reactant  and a reaction inhibitor together with a photolyzable  source of halogen acid, which upon exposure to a  light-image liberates said first reactant for reaction  with a second reactant to produce a visible image,  contains a controlled small amount of an acid accep› tor for reducing backgrounding and increasing con› trast in the resulting print.  [57]  ABSTRACT  8  II  E  D  LOq REL4T!VE EXPOSURE  13 Claims, 1 Drawing Figure 