The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 11, 1993
Filed:
Apr. 30, 1992
Ross Fielding, Knutsford Cheshire, GB;
Ilford Limited, Knutsford Cheshire, GB;
Abstract
There is described a concentrated developer solution which comprises from about 20 to about 60 g/l of dihydroxybenzene developing agent, preferably hydroquinone, from about 0.5 to about 3.0 g/l of an auxiliary developing agent, preferably 1-phenyl-3 pyrazolidinone, from about 300 to about 500 g/l of potassium sulphite and which is buffered to a pH of from about 8 to about 10 with a buffering agent other than an alkanolamine and which comprises sufficient organic solvent other than an alkanolamine to dissolve the hydroquinone. Such a concentrated developing solution which contains a high concentration of potassium sulphite has when diluted a long useful life and produces images of low graininess.