Abstract: A method of compressing oxygen includes passing the oxygen into a vessel 12 containing finely divided material. Next a driving gas, for example, air is compressed to a greater pressure than the oxygen and passed through the vessel 12 and the bed of material contained therein which creates a plug flow effect such that the oxygen is compressed by the air substantially without back-mixing.

Abstract: A rotary gas recovery system includes a fixed adsorption tower (12) divided into a plurality of sections (12') arranged in the circumferential direction around a central axis and filled with adsorbent (11), a first manifold (14) on one side of the tower having opening (14a, 14b) for supplying and discharging gases to and from the fixed adsorption tower, a second manifold (15) having openings (15a-15d) for supplying and discharging gases through the first manifold, and a movable valve plate (16) slidably interposed between the first manifold (14) and second manifold (15) and having openings (16a, 16b) for sequentially connecting the openings in the first manifold with the openings in the second manifold by a continuous motion.

Abstract: Direct-positive photographic silver halide emulsion which contains a dye having a 5,6-dihydropyrrolo[2,1-a]isoquinoline ring is disclosed. Said emulsion has a high speed, produces high contrast images, has no color stain with any remaining dye after processing and causes only small depression in the maximum density.

Abstract: Photographic additives in particular water-insoluble photographic additives are rendered easier to incorporate into photographic layers by finely dividing them, mixing them with a finely divided water soluble substance and compressing the resulting mixture into the form of a tablet. The tablets which contain from about 1 to 50% by weight of the photographic additives are then dissolved in the coating composition and this disperses the water insoluble additive uniformly throughout the coating composition.

Abstract: Photographic additives in particular water insoluble photographic additives are rendered easier to incorporate into photographic layers by finely dividing them, mixing them with a finely divided water soluble substance and preparing granules of the mixture using a hydrophilic colloid as the binder. The granules which contain from about 1 to 50% by weight of the photographic additives are then dissolved in the coating composition and this disperses the water insoluble additive uniformly throughout the coating composition.

Abstract: Novel methyne dyes comprising two auxochromic groups of the type used in a cyanine or merocyanine dye linked by a carbon atom chain wherein each of the carbon atoms have an unsaturated linkage to at least one adjacent carbon atom in the chain and at least one pair of carbon atoms in the chain being joined by a triple bond or, in an alternate resonance form, the chain including three consecutive carbon to carbon double bonds. The dyes are useful as spectral sensitizing dyes for silver halide emulsions and as intermediates for synthesizing chain-substituted methine dyes.

Abstract: The present invention relates to light-sensitive photographic material with a light-sensitive heavy metal compound, e.g. a silver halide, and a spectral sensitizer. The spectral sensitizer is a compound in which the radicals of a sensitizing dyestuff are covalently bonded to amino, imino, hydroxyl, mercapto, carboxylic acid or carboxylic acid amide groups of a natural hydrophilic colloid, preferably gelatin.The invention also relates to new sensitizing dyes which are dinuclear cyanine dyes or merocyanine dyes which have attached either to a heterocyclic nucleus of the dye or to its methine chain a group which is reactive with a hydrophilic colloid.

Abstract: Novel sensitizing dyes containing isoindole nuclei. These dyes can be used as spectral sensitizers for silver halide emulsions.

Abstract: Novel methyne dyes comprising two auxochromic groups of the type used in a cyanine or merocyanine dye linked by a carbon atom chain wherein each of the carbon atoms have an unsaturated linkage to at least one adjacent carbon atom in the chain and at least one pair of carbon atoms in the chain being joined by a triple bond or, in an alternate resonance form, the chain including three consecutive carbon to carbon double bonds. The dyes are useful as spectral sensitizing dyes for silver halide emulsions and as intermediates for synthesizing chain-substituted methine dyes.

Abstract: New cyanine dyes, comprising at least one of the following nuclei (or derivatives thereof):1. 2,3,3-trimethyl-5-phenyl-sulfonyl-indolenine;2. 2,3,3-trimethyl-5-benzoyl-indolenine;3. 1-aryl or alkyl-2-phenyl-5-phenyl-sulfonyl-indole;4. 1-aryl or alkyl-2-phenyl-5-benzoyl-indole,Are desensitizers for silver halide negative emulsions and useful electron acceptor spectral sensitizers for direct positive silver halide emulsions.

Abstract: Surface sensitive photographic low pAg silver halide emulsions and elements are provided which contain (1) a photographic infrared spectral sensitizing dye having a polarographic cathodic halfwave potential more positive than about -1.20 volts, said dye being employed in the emulsion at a concentration which results in at least about 0.3 log E desensitization of a test portion of the emulsion, when the test portion of the emulsion is coated on a support, sensitometrically exposed and developed and (2) a silver complexing azaindene in an amount effective to reduce the desensitization caused by the spectral sensitizing dye. Photographic emulsions in accordance with this invention exhibit higher speeds in the spectrally sensitized region (i.e., higher minus blue speeds) than prior art surface-sensitive emulsions. In addition, use of the emulsions in accordance with this invention permits the use of higher dye concentrations and results in emulsions having excellent keeping qualities and much lower fog levels.

Abstract: Colloidally stable dispersions of a spectral sensitizing dye are formed directly in water without the use of an organic solvent. The process of the invention involves mixing the dye particles with water to form a slurry and then homogenizing or milling the slurry at an elevated temperature in the presence of a surfactant to form finely divided particles uniformly dispersed in the water.

Abstract: Methine dyes comprising first and second nuclei joined by a double bond or a methine linkage. The first nuclei may be eitherA. a pyrido nucleus joined at the 4- or 6-carbon atom thereof to said double bond or methine linkage or,B. a 5,6-dihydropyrido nucleus joined at the 4- or 5-carbon atom to said double bond or methine linkage.The pyrido or dihydropyrido nucleus can have fused to its 1,2-side the atoms required to complete a ring containing 5 or 6 atoms. The second nuclei may be either the same as (a) or (b) or can be of the type typically used in cyanine styryl and merocyanine dyes. Such dyes are useful filter dyes and spectral sensitizers for silver halide compositions. Also described are intermediates useful in the synthesis of said dyes.

Abstract: A method for spectrally sensitizing a photographic light-sensitive emulsion, which comprises dissolving a photographic spectrally sensitizing dye having an amidinium ion auxochrome in an organic solvent containing a substantially water-free acid having a pKa not exceeding about 5, and adding this dye-containing acid-organic solvent solution to a light-sensitive emulsion.

Abstract: Sensitization of silver halide emulsions by merocyanines and cationic cyanines and the stability of this sensitization is improved by addition of heterocyclically substituted thioureas of the formula ##EQU1## wherein R.sup.1 is alkyl, alkenyl or arylR.sup.2 is alkyl, cycloalkyl or aryln is 0 or 1, andZ completes a 5- or 6-membered heterocyclic group, preferably one which also contains a sulfur atom.

Abstract: A direct positive silver halide photographic emulsion containing1. at least one dimethine dye having the general formula (I): ##EQU1## 2. AT LEAST ONE COMPOUND HAVING THE GENERAL FORMULA (II): ##SPC1##3. at least one compound having the general formula (III) ##EQU2## or the general formula (IV) ##SPC2##wherein Y, Y.sub.o, Z, L.sub.1, L.sub.2, R.sub.o, m, n, X, Z.sub.1, R.sub.1, X.sub.1, a, p, q, Y.sub.1, Y.sub.2, m.sub.1, R.sub.3, r, X.sub.2 and X.sub.3 are as hereinafter defined.

Abstract: A direct-positive photographic element is described which comprises a support and a spectrally-sensitized light-sensitive silver halide emulsion layer containing fogged silver halide grains wherein the said emulsion is spectrally sensitized by means of a dye containing a pyrrolo[ 2,1-b]thiazole nucleus which may be substituted and carry one or more fused-on rings, the said nucleus being linked by the 5- or 7-carbon atom thereof, directly or through a dimethine chain to another nitrogen containing heterocycle.

Abstract: Light-sensitive photographic emulsions are provided which feature at least one methine dye containing a 1H-imidazo[4,5-b]pyrazine nucleus.

Abstract: Novel dyes are described for sepctrally sensitizing direct-positive silver halide emulsions comprising fogged silver halide grains. The dyes correspond to the formula: ##SPC1##Wherein:R.sub.1 is hydrogen, an alkyl group, an aryl group, or an acyl group,Each of R.sub.2 and R.sub.3 represents hydrogen, carboxyl, sulpho, nitro, cyano, halogen, an alkyl group or an aryl group,Each of L.sub.1 and L.sub.2 represents a methine group, m is 1 or 2, Y is O, S, Se or ##EQU1## R.sub.4 represents an aliphatic group or an aromatic group, X.sup.-represents an anion but does not exist when the molecule itself contains an anionic group, and Z represents the atoms necessary to close a fused-on benzoor naphtho-ring carrying one or more substituents at least one of which is a COR.sub.5 or SO.sub.2 R.sub.6 group wherein R.sub.5 is alkyl, aryl, hydroxyl, O-alkyl, NH.sub.2, NH-alkyl, NH-aryl, ##EQU2## AND R.sub.6 is alkyl, aryl, NH.sub.

Abstract: A silver halide photographic emulsion for direct positives, containing a fluorene compound having at least one nitro group as a substituent.