Eastman Kodak reversal film duplication stock for (semi)professional use. Replaced Type 5265. Type 7387 introduced in 1964 as improved version. Difficult to see the difference (BL).
Subtractive 3 color: dye diffusion process, still photography
“Kodak Instant Print Film PR-10 was based on a dye release system that used ballasted preformed dyes and reversal emulsion instead of dye developers and negative emulsion. Processing started when the film passed between pressure rollers that ...
Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, p. 242.
cross section scheme of Ektachrome Type 5257 (and 5258). Scource: Groet, N.H./Murray, T.J./Osborne, C.E. (1960): Two High-Speed Color Films and a Reversal Print Film for Motion Picture Use. In: JSMPTE Vol. 69, p. 816.