Film Washi "F" 135

Overview

"F" is not a photographic film by design: it is a fluorographic X-ray film, the stock used for mass lung screening, coated in another factory by machine and converted to camera formats by Film Washi in Brittany. Unlike the duplitized dental and medical sheet film photographers usually repurpose, it carries a single emulsion on one side of a 100 µm polyester base, so it needs no special regime and develops as an ordinary black and white negative in ordinary chemistry. Film Washi publishes 9 min in Rodinal 1+25, 8 min in Ilfotec LC29 1+19, 11 min in D-76 1+1 and 4.5 min in HC-110 dilution A, all at 20 °C, and instructs you to fall back on Ilford FP4 times and dilutions for any developer not on that list. There is no anti-halation layer, so highlights bloom back through the base as a soft halo; the datasheet rates the grain high and the contrast medium, and notes the diffusion is markedly stronger in 135 than in 120 and changes with the angle of the light. The same missing layer pipes light down the roll, so Film Washi instructs you to load in shade and shoot six blank frames before your first picture, and to keep the cassette in a dark bag before and after shooting. It is orthochromatic, sensitive to a maximum of 575 nm: reds record dark, and a red safelight is permitted — one of the few Washi stocks you can develop by inspection. It ships in a recycled cassette with no DX code, so set ISO 100 by hand; Film Washi does not recommend recycled cassettes in fully automatic or motorised cameras. Sellers describe the medical base as blue-tinted where the datasheet says only "polyester, 100 µm", and photographers report the emulsion is thin and awkward on a developing reel — handle the wet film by its edges and judge the result after scanning and inversion, not on the light table.