Eastman-kodak Company

David J Young

Alan R Pitt

Trevor J Wear

Danuta Gibson

Julian C Caesar

Scott A King

Anthony Earle

Edward C Glover

Rachel Richardson

John T Wear

This invention provides an oil-in-water emulsion, particularly a photographic dispersion, having a reduced droplet size in the oil phase obtained by an increase in the viscosity of the aqueous phase prior to homogenization of the oil and aqueous phases; methods of forming thereof and to the use of the emulsion in a silver halide based photographic system.

Method of forming photographic dispersion

Homogenizing apparatus

It is known to wash dispersion noodles in a `batchwise` fashion in which the noodles are retained in a kettle or kettle and water is sprayed onto the surface of the noodles. Agitation is achieved by bubbling air into the kettle from the bottom. Described herein is a method and apparatus for continuously washing dispersion noodles. The apparatus includes continuous pipe work in which the noodles are washed, the pipe work including at least one separating device (10) for separating the noodles from the water in which they have been washed. The device (10) comprises a housing (12) having an inlet (14) and an outlet (16). A separating element (22) is located in the housing (12) between the inlet (14) and the outlet (16) and is surrounded by a collection chamber (24), the element (22) comprising a tube of mesh material through which water passes into the collection chamber (24) and which is then drained off through drain (32). The housing (12) includes jets (28, 30) through which water, hot or cold, or steam can be introduced for cleaning the device (10). Water jets (34, 36) are provided in the outlet (16) for introducing clean water to the noodles.

Washing of dispersion noodles

In order to maintain product quality control and process control when producing photographic materials, it is necessary to measure droplet size of dispersions or dispersion melts utilized to produce such materials. Known methods of measuring the droplet size require off-line techniques and there is no readily available process control. Described herein is an on-line technique for the measuring of droplet size which provides such process control.

Measurement of droplet size in a photographic dispersion

Dispersions and emulsions comprising a fatty acid ester to reduce

Surfactants useful as dispersing aids in the preparation of compositions comprising a hydrophilic colloid having hydrophobic particles dispersed therein have the structure ##STR1## wherein R is H or methyl provided that when each n=1, each R is methyl;

Surfactants and hydrophilic colloid compositions and materials

It is known that the properties of powders affect the ease or difficulty of handling in many industrial processes. In may cases, the only way to test the suitability of a particular powder for a given system is to pass a sample of that powder through the system. This involves using a large quantity of the material with the uncertainty that the properties of the material are in fact suitable for that system. Described herein is a test device which allows certain properties of a material in powder form to be determined without the need for large quantities of material. The device (10) comprises a frame (12, 14, 16, 18, 20) in which is mounted a curved test surface (26). An aperture (22) is provided in a top member (14) of the frame (12) to allow the material being tested to fall on to the test surface (26) to form a `footprint`. The `footprint` can then be measured to provide an indication of the properties of the material prior to it being introduced into a system in bulk.

Powder tester

The invention provides a photographic dispersion for inducing dye stability in the eventual photographic product. The invention provides in a first aspect a photographic dispersion comprising a photographic coupler and a solvent therefore wherein the solvent is solid at its temperature of fade concern thereby to promote dye stability in use. The invention also provides a photographic coupler and a solvent therefor wherein the solvent is an alkyl alcohol or an optionally substituted dialkyl or diaryl phosphate. The coupler may have a ballasted chain having a matched molecular structure thereby to further promote dye stability in use.

Dye stability with solid coupler solvent

A sampling device comprising an outer tube and an inner tube that is eccentrically mounted for rotation within the outer tube, the inner and outer tubes being disposed in spaced, parallel relationship so that relative rotation therebetween cuts a sample of bulk material and retains that sample for subsequent removal.

Bulk material sampling device

The invention provides a composition comprising a hydrophilic colloid and a surface active agent characterised in that the surface active agent is a compound having the formula ##STR1## wherein each of R.sub.1, R.sub.2 and R.sub.3 independently is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group;

Hydrophilic colloid compositions for photographic materials

A test element is provided which can detect and measure extremely low concentrations of formaldehyde in the environment. The test strip comprises a support having thereon a formaldehyde-sensitive layer comprising an inert formaldehyde-permeable binder which stabilizes sulphite ions against aerial oxidation having dispersed therein pararosaniline or an acid derivative thereof and sulphite ions. The test element requires no processing and can be fixed to obtain a permanent record.

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Chorleywood, United Kingdom

David J Young