Patent GB-742222-A (GB)
Title: Improvements in the preparation of photographic silver halide emulsions
IPC: G03C1/043
Filed: 1953-11-09
Abstract: 742,222. Stabilizing photographic emulsions. KODAK, Ltd. Nov. 9, 1953 [Nov. 8, 1952], No. 31024/53. Class 98 (2). A light-sensitive silver halide emulsion of which the light-sensitivity has been increased by the incorporation therein of an alkylene oxide polymer or a derivative, also contains a simple mercury salt of an organic or inorganic acid, a molecular compound of a mercury salt with an organic compound containing a basic nitrogen atom, or an organic compound of mercury in which the mercury atom is attached by a non- ionic bond to an organic nucleus and by an ionic bond to an anion. The alkylene oxide polymer may be polyethylene oxide, di-(polyethylene-glycoxy)-decane, or polyethylene oxide oleyl ether, or may be a derivative such as a polyalkylene ether, ester, or amide or a condensation product of an alkylene oxide with a hexitol ring dehydration product. The mercury compound may be added to the emulsion in a solvent such as water, a lower alcohol or a ketone, at any stage before coating, e.g. after final digestion. The emulsion may be dyesensitized, and may be chemically sensitized, in addition to the sensitization with an alkylene oxide polymer, by digestion with naturally active gelatin, or by addition of sulphur compounds, salts of ruthenium, rhodium, palladium, iridium, or platinum (antifoggants in higher amounts), gold salts, stannous salts, polyamine such as diethylene triamine and spermine, or bis - (# - aminoethyl) - sulphide and its watersoluble salts. In examples, speed, gamma and fog data before and after incubation are given for (1) an emulsion sensitized with a sulphur compound, potassium chloroaurate and polyethylene oxide, with and without (as antifogging compound) bis-(2-amino-5-iodopyridine hydriodide) mercuric iodide; (2) an emulsion sensitized with a sulphur compound, potassium chloroaurate, and a mixture of cyanine dyes, with and without polyethylene oxide oleyl ether as additional sensitizer and with and without bis-(2-amino-5-iodopyridine hydriodide) mercuric iodide in varying amounts as antifogging compound; (3) an emulsion sensitized with sulphur, gold, and stannous compounds with and without polyethylene oxide, and with polyethylene oxide and (2-amino-5-iodopyridine 2 . HI.HgI 2 , mercuric chloride (two different quantities), or pyridyl mercuric chloride; (4) an emulsion sensitized with sulphur and gold compounds (a) with no further addition, (b) with triethylene tetramine and polyethylene oxide, (c) and (d) as (b) with different quantities of (2-amino-5-iodopyridine) 2 .HI.HgI 2 , (e) as (b) with mercuric chloride, and (f) as (b) with pyridyl mercuric chloride; (5) an emulsion sensitized with sulphur and gold compounds (a) with no further addition, (b) with polyethylene oxide, (c) as (b) with (2-amino-5-iodopyridine) 2 .HI.HgI 2 , and (d) and (e) as (b) with two different quantities of mercuric iodide; (6) an emulsion sensitized with ammonium chloropalladate with (a) no further addition, (b) with polyethylene oxide, (c) as (b) with (2-amino-5-iodopyridine) 2 .HI.HgI 2 , and (d) as (b) with mercuric iodide; (7) an emulsion sensitized as in (2) with (a) no further addition, (6) and (c) polyethylene glycol oleyl ether and K 2 Hg(CN) 4  in different amounts, and (d) polyethylene glycol cetyl ether and K 2 Hg(CN) 4 ; and (8) an emulsion sensitized with allyl thiourea and potassium chloroaurate with (a) no further addition, (b) polyethylene oxide, and (c) and (d) 8 - chloromercuriquinoline in two different amounts. Specifications 235,211, [Class 98 (ii)], 380,431, 380,851, [both in Group IV], 548,019, 592,676, 600,058, 602,158, 602,160, 618,061, 636,140, 658,592, 661,645, 663,019, 664,230, 680,593, 682,355, 742,219, 742,220, 742,221 and 742,224 are referred to.