Abstract: Hydroquinone esters are incorporated in photographic elements for color diffusion transfer assemblages and release a competing developer upon contact with a processing composition, to terminate further dye release. The hydroquinone esters are employed in a concentration sufficient, upon hydrolysis, to reduce substantially all the silver in the silver halide emulsion.

Abstract: The invention relates to thermally insulating materials. It refers to a thermally insulating slab consisting of entangled refractory fibres, the major portion of the fibres being substantially parallel with the main faces of the slab, characterized in that the back of the slab bears a plurality of furrows or grooves distributed over the back. The slab is used for the insulation of furnaces and the like.

Abstract: The invention relates to a heat-insulating slab formed by a plurality of continuous strips maintained in assembly side by side, each strip comprising entangled refractory fibres the major portion of which is perpendicular to the two main faces of the slab, the strips being maintained in assembly exclusively by means of a plurality of lines, ribbons or cords of an organic synthetic matter which adhere to the strips and are applied to the two main faces of the slab perpendicular to the strips. This slab is useful for insulating the inner surfaces of furnaces.