Abstract: A cassette which is adapted to contain a length of photographic film wound on a spool and which has an exit-slot from which the film is pulled from the cassette being characterized in that it comprises a scroll control chamber which is formed from a strip of light opague resilient material of such dimensions that it fits into the cassette and is retained therein by means in the cassette, the width of the greater part of the strip being such that it is disabled by means at each end of the cassette from touching the inside wall of the cassette and the width of the lesser part of the strip being such that the end of this part of the strip abuts the inside wall of the cassette, the scroll control chamber being so located in the cassette that it is able to accommodate a length of photographic film wound on a spool, the leading end of the film being led from the spool through the lengthwise gap in the scroll control chamber, then passing between the inside wall of the cassette and the outer wall of that part of the

Abstract: An elongated two-color light-transmitting filter strip of a light-transmitting material has a first zone of its length which transmits light in a first of two mutually exclusive wavebands, a last zone which transmits light in the second of two mutually exclusive wavebands, and a middle zone of the strip having discrete elements which transmit light in the first of the two mutually exclusive wavebands and discrete elements which transmit light in the second of the two mutually exclusive wavebands, the elements having equal areas and being so arranged that there is a progressive change in the transmission of light in the two mutually exclusive wavebands along the middle part of the strip and being so arranged that there is no single line of demarcation dividing that part of the filter which transmits light only in the first of the two mutually exclusive wavebands from that part of the filter which transmits light only in the second of the two mutually exclusive wavebands.

Abstract: A lamphouse for use with an enlarger head in the production of prints on variable contrast or on conventional photographic material which consists in part of a light source from which light is directed to a fixed apertured plate. There is on one side of the apertured plate remote from the light source a composite filter, one portion of which passes light in one of two mutually exclusive wavebands and the other passes light in the other of the two mutually exclusive wavebands. The composite filter is moveably mounted in relation to the apertured plate so that in one position the light passing the filter is in all of one of the mutually exclusive wavebands and in the second position the light passing the filter is in all of the other of the mutually exclusive wavebands. In intermediate positions of the filter a varying mixture of light of the two wavebands is transmitted.