New Sigmoid Scene to Display mapping

Not really, each medium (film and paper) has its own gamma, which is the slope in log/log space, aka the exponent in linear space. So the film printing process as a whole is log/log tone mapping overall.

The paper hardness, in darkroom, was chosen based on the contrast of the film, to compensate it. If the film was already very contrasted (large Dmin - Dmax), the lab techs would chose a low paper grade. And the other way around. So it’s consistent with what it represents, and it has never been an orthogonal setting, more like an adjustment variable.

I’m all for that, but outside of splines, which are very generic with the oscillatory drawbacks we have seen, you might end up needing 3 or more different kinds of sigmoids to control the shape, which may not, at the end, solve the initial problem of degrees of freedom reduction.

It’s not much about color spaces, rather than… OCIO ships LUTs, that is someone (Troy Sobotka) pre-computed the view-transform with sane dynamic range parameters times a couple of more/less contrasted variants and put that into a static file. darktable filmic’s re-uses the same logic but with an interactive UI, which gives plenty of options for users to harm themselves.

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