British Kinematography (1950)

84 BRITISH KINEMATOGRAPHY Vol. 16, No. 3 with a simple gelatine-coated film rather than with an emulsion-coated material. The principal reason for starting with a silver-halide emulsion is to produce a silver image sound track, although it also appears to be the practice at present to print the frame margins at the same time as the track, and to process both of them before the transfer of the three component dye images. Technicolor Sound Track Much thought and several patents have been devoted to the possibility of producing a sound track by dye-transfer from a matrix in the same way as the picture images are formed ; but even Technicolor do not seem to have been able to overcome the difficulties in reproducing sound from a dye image track — particularly when such a track must suffer from some diffusion. The latest line of approach seems to be to form a track of an insoluble iron salt, which is known from experience with two-colour processes to be substantially opaque to infra-red rays and therefore satisfactory for sound reproduction with normal photo-cells. One of the proposed procedures is to sensitise locally the track area of a gelatine-coated blank film with ferric ammonium oxalate before seating it on the usual type of imbibition pin-belt ; and then, after application of a matrix bearing yellow-dyed gelatine relief images, in both sound and picture areas, to expose the light sensitive area of the blank film through the dyed sound track image of the matrix. When the blank and matrix have been in contact long enough for the dye to have transferred, the two films are parted, the matrix being wound up ready for further use and the blank continuing into a bath of potassium or sodium ferricyanide for the development of the printed sound track image. After treatment in the ferricyanide bath, the blank is washed to remove the soluble unexposed iron salts from the track area and then dried before returning to the pin-belt to receive the magenta and cyan component images.2 The procedure involved in making 35 mm. Technicolor release prints from 16 mm. Kodachrome originals is obviously much the same as that required when working from so-called " Technicolor Monopack." Whereas the supply of 35 mm. " Monopack " was restricted at one time, 16 mm. Kodachrome has been freely available in America for many years, yet so far as I know no 35 mm. release printing laboratory, other than Technicolor, has ever made successful use of the fact. Dufaychrome Cameras Dufaychrome is next on the chart — a process about which I could say much, but about which I propose to say very little. We have now completed two three-strip cameras,3 and have four more in hand — in fact the combined total of Technicolor and Dufaychrome three-strip cameras now being built in this country must constitute a record in the history of colour kinematography. Certainly there is no indication that the " beam-splitter " camera will be relegated to the museum shelf. II. INTEGRAL TRIPACK PROCESSES Next in line on the chart are the integral tripack processes, and the first of these in alphabetical order is Anscocolor.4 I had hoped to be able to project a recent example of Anscocolor printed from Type 735 camera film, but although 1 asked Denham Laboratories they have been unable to help me. It certainly would have been interesting to have seen something of either "Alice in Wonderland " or " The Man in the Eiffel Tower." A recent paper by Bates and Runyon5 shows that the Ansco technicians have gone deeply into the theory and practice of their process. This paper deals much more fully with the control problems involved in processing a multi-layer colour material than any information obtained from Germany.