Patents by Inventor John H. Bigelow

John H. Bigelow has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Silver halide emulsion containing tetrathiocino diisothiazoles as antifoggers
    Patent number: 4210716
    Abstract: Compounds of the general formula: ##STR1## wherein X is cyano or ##STR2## Q is OR.sub.1 or --NR.sub.2 R.sub.3 ; R.sub.1 is hydrogen or alkyl of 1-4 carbon atoms, R.sub.2 is hydrogen or methyl, and R.sub.3 is hydrogen or alkyl of 1-4 carbon atoms, are incorporated into light sensitive silver halide emulsions to improve their sensitometric characteristics.
    Type: Grant
    Filed: January 31, 1979
    Date of Patent: July 1, 1980
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: John H. Bigelow
  • 4,7-Dihydroxybenzimidazole hydrobromide as antifogger
    Patent number: 4131467
    Abstract: Compounds of the general formula ##STR1## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions and X.sup.- represents Br.sup.-, Cl.sup.- or I.sup.- are incorporated into light-sensitive silver halide emulsions to improve their sensitometric characteristics. In general, these compounds act as antifoggants by restraining fog growth but at the same time act as development accelerators by increasing gradient and Dmax, usually at some speed loss.
    Type: Grant
    Filed: November 23, 1977
    Date of Patent: December 26, 1978
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: John H. Bigelow
  • Macrocyclic polyamines as sensitizers for silver halide emulsions
    Patent number: 3930867
    Abstract: Photographic silver halide emulsions are prepared which have their sensitivity increased by the addition of at least one macrocyclic polyamine, a salt, or a metal chelate thereof, said macrocyclic polyamine having the formula--(NH -- (CH.sub.2).sub.n).sub.m --Where m is 4-7 and each n is independently 2-5.
    Type: Grant
    Filed: January 7, 1974
    Date of Patent: January 6, 1976
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: John H. Bigelow