& Foma currently produce kits for reversal processing. Kodak formerly offered a kit ("Direct Positive Film Developing Outfit") for reversal processing of its now-discontinued Panatomic X film, which doubled the effective film speed from 32 to 64. The bleaching bath used potassium dichromate and sodium bisulfate; the redeveloper was a fogging developer, and so unstable that its shelf-life after mixing was only slightly longer than the amount of time needed to process a single roll. This was replaced with a "T-Max Direct Positive Film Developing Outfit", which uses potassium permanganate and sulfuric acid in the bleach. In this kit, the fogging redeveloper is stable, but the bleach is not, with a shelf-life, once mixed, of no more than two weeks. dr5 Chrome process, which produces black-and-white transparencies from most traditional halide (i.e., non-chromogenic) black-and-white negative films. Kodak Tri-X Reversal Film 7266 and Kodak Plus-X Reversal Film 7265 are black-and-white reversal films used for movie-making. Ilford has published a reversal process applicable to all current B&W emulsions, but recommended for Pan F+, FP4+, and Delta 100. Pros and cons Pros Shows what exactly was captured on film without printing. More accurate color translation when digitizing. There is no need for color inversion processes. Much faster digitizing on professional scanner machines. In general, slide film produces much more vibrant colours than negative film. Finer grain, better resolution and sharpness compared to color negative films. Cons Generally fewer stops of exposure latitude when compared to color negative film. Lower film speeds than color negative. Typically higher priced. Uses Viewing Finished transparencies are most frequently displayed by projection. Some projectors use a sliding mechanism to manually pull the transparency out of the side of the machine, where it is replaced by the next image. Modern, advanced projectors typically use a carousel that holds a large number of slides; a mechanism automatically pulls a single slide from the carousel and places it in front of the lamp. Small externally lit or battery-powered magnifying viewers are available. In traditional newsrooms and magazine offices slides were viewed using a lightbox and a loupe, which allowed rapid side by side comparison of similar images. Slide copier A slide copier is a simple optical device that can be fastened to the lens mount of a camera to enable slide duplicates to be made. Whilst these devices were formerly used to make duplicates on to slide film, they are often