While nowadays, redscale film can be bought premade, it is based on a simple technique: In essence, photographic film is reversed and wound upside-down into an empty film canister. When used, it is exposed from the wrong side creating beautifully tinted images with colors ranging from maroon, to red, to organge, to yellow.
You can find more beautiful shots in our Redscale groups, or in a tag search for redscale+film.
Photos from Trapac, ozgecan, celia gómez de villavedón, cherryrae., slimmer_jimmer, raquel fialho, and 25ThC.