Abstract: Apparatus for developing exposed diazotype sheet material in which an accurately metered amount of liquid developer is applied to the sheet material by an applicator roller. The roller surface is essentially smooth and liquid developer is applied to the roller surface in an amount metered by a metering blade assembly which includes a flexible support member carrying a resilient backing layer which, in turn, carries a fine mesh screen held in contact with the smooth surface of the roller. The screen includes intersecting filaments and opposed, flattened lands on opposite surfaces of the screen and located at intersections of the filaments, the screen having a predetermined thickness between opposed flattened lands.

Abstract: Apparatus for developing exposed diazotype sheet material in which an accurately metered amount of liquid developer is applied to the sheet material by an applicator roller. The roller surface is essentially smooth and liquid developer is applied to the roller surface in an amount metered by a metering blade assembly which includes a flexible support member carrying a resilient backing layer which, in turn, carries a fine mesh screen held in contact with the smooth surface of the roller. A sheet of smooth, essentially continuous material is interposed between the screen and the roller surface when the apparatus is not in use and is retracted to enable direct contact between the screen and the roller surface when the apparatus is in use.