Appeal No. 1998-1732
Application 08/608,321
silicic acid sol and gelatin” (page 3, line 15) indicates that
gelatin may be present or absent, and EP ‘961 discloses such a
precipitation in the absence of gelatin (page 3, line 48).
The ratio of onium compound to colloidal silica is preferably
0.5x10- to 5x10- mol of onium compound per 90g of SiO (page3 3 2
3, lines 55-57). The examiner calculates that the EP ‘092
examples include colloidal silica:onium ratios within the
appellants’ range of 3-400 (answer, pages 5-6), and in their
reply brief the appellants do not challenge the examiner’s
calculations. The silver halide emulsions can be prepared
under conditions of controlled flow rates (page 4, lines 16-
18). Steps of physical ripening (page 6, lines 52-53),
desalting the reaction medium and redispersing the silver
halide obtained (page 4, lines 41-43), chemically ripening the
silver halide (page 4, lines 44-56; page 7, line 7), and
adjusting the ratio of colloidal sol to silver halide,
apparently to keep it in the 0.5-1.0 weight ratio range (page
5, lines 51-58), can be used.
Thus, it is seen that there is substantial overlap
between the EP ‘092 method and that recited in the appellants’
claim 1. The appellants’ claim 1, however, requires that the
-5-
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