I keep seeing unbelievable claims and diagrams for the colour space of reversal film, like this one. Its complete parent webpage is here if you want a laugh. The latest instance seen was in a recent magazine article that showed the gamut of a "typical reversal film" as a perfect RBG triangle(!) with its blue point actually poking out of the side of the CIE horseshoe. See file below; the blue-dotted and yellow triangles are the AdobeRGB and sRGB spaces respectively, while the darker spectrum is supposed to represent film. The reason I find such diagrams unbelievable is because the "primaries" of colour film are actually CMY dyes, and so can't possibly be represented by singular RGB points. I would expect to see at least some rounding of the corners and sides. Plus no viewing illuminant is specified along with those impossible triangles, and no account seems to have been taken of the film's initial RGB filtration either. I don't want to rekindle a film v digital war here, but it would be nice to know what RBG colour space is actually big enough to hold the gamut of film. I'm aware that there might be some theoretical saturated cyans that may hang outside of an RGB triangle, but first let's get close to a realistic model of film's colour space before we worry about that. Question is then, has anyone seen, or got a link to a believable diagram or specification for a "typical" reversal film gamut? I have the data sheets for most of Fuji's and Kodak's films with the dye absorbtion curves in them, and I'm working on a theoretical transform to CIE X,Y,Z locations. The maths isn't easy! I have a couple of published papers to guide me, but it would obviously be quicker if someone had already done the job or knows of some suitable transform software. I don't particularly want to re-invent the wheel.