Abstract: A versatile, multiple-slot, dual cavity, slide/extrusion hopper for assembling and coating a composite layer comprising a plurality of highly uniform, superposed compositions, and a method for determining the dimensions of the hopper are disclosed. The hopper is suitable for photographic applications and other applications requiring highly uniform layers. The hopper is versatile in that it can accommodate coating compositions that range from Newtonian to substantially shear thinning and in that fewer than the total number of elements may be supplied; the slide offsets between elements are suitable for both merging layers and for the top layer alone. The height of the secondary slot is preferably greater than the height of the primary slot. The method provides optimal cross-sectional shapes for the cavities. Versatility is achieved without greatly increasing the height or thickness of the elements.

Abstract: A method of coating moveable supports at high speeds comprises moving a support along a path through a coating zone; forming two or more layers including a topmost layer of coating liquids to form a liquid coating composition; and applying the liquid coating composition to the moving support wherein the topmost layer of the liquid coating composition is shear thinning.

Abstract: A method of coating moveable supports at high speeds comprises moving the support along a path through a coating zone, forming two or more layers of coating liquids including an actual top coat layer to form a liquid composition (with a slide hopper coating a plurality of outlets for coating liquids) and applying a starting top most layer of coating liquid, which layer has a lower viscosity than that of the actual top coat layer, to the liquid coating composition either through the first outlet of the hopper or through an x-hopper located between the first outlet and coating zone, applying the coating composition and starting top most layer, and terminating the application of the starting top most layer when the coating operation is at steady state. Apparatus for carrying out this method is also described.

Abstract: The present invention is a method determining where to add hardener in a multilayer coating pack on a web fed through a coating station. The process includes determining the frequency and amplitude of the process noise associated with the coating station, determining the growth factor as a function of frequency on the incline surface and repeating these two steps for each of the layers in the coating pack. The plurality of growth factors obtained as a function of frequency is converted into a plurality of wave amplification versus frequency. After the plurality of wave amplitudes versus frequency is determined, one then selects from this plurality the one which is below a predetermined value in order to reduce coating cross streaks.

Abstract: A method of reducing the tendency toward formation of ripple imperfections in the coating of multilayer photographic elements is disclosed. Coating compositions are prepared for upper, middle, and lower gelatin-containing layers of a layered mass. The middle layer has a gelatin concentration within three weight percent of each of the upper and lower layers and the upper, middle, and lower layers each have a viscosity that differs from a norm by no more than 15%. A laminar flow of a layered mass including the coating compositions is formed and then received as a layered coating on a moving support. A multilayer photographic element is also disclosed.

Abstract: A method for reducing the tendency toward the formation of ripple imperfections in the coating of a plurality of layers of liquid photographic compositions or moving webs is disclosed. Conditions for coating the compositions are determined according to a given formula to keep the ripple value below 35. The coating compositions are formed into a laminar flow of a plurality of distinct layers including the photographic compositions as upper, middle, and lower layers. The flowing plurality of layers is then received as a layered mass on a moving web. A method for predicting the tendency toward the formation of ripple imperfections in the coating of a multilayer photographic element is also disclosed.

Abstract: In a curtain coating apparatus for the coating of photographic film and paper webs and the like, the line of impingement of the curtain on the moving web is controlled by providing a pressure controlled zone on one side of the flowing curtain. Small changes in the static air pressure in the zone cause the position of the curtain to move without disturbing the quality of the curtain. Wetted side walls of the pressure controlled zone can serve as edge guides for the curtain.