I would certainly hope not.
I would have loved to use the tone eq for what I have described, but I find it an excellent tool for more granular changes, and at the same time not granular enough, for certain levels of change. See below
Please as I keep noting, I am not an optics or physics expert, just an end user, which hopefully also counts, as a member of the ecosystem.
Sigmoid, filmic, base curve or any similar tools, all attempt to define in various ways, the curvature of the transform.
If we look at this issue as the size of a brush, one would have different sizes of brushes for painting.
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Global - changes like in exposure module, where I would expect a simple multiplier is used mathematically when you change exposure, so all values in the entire image are adjusted. Broad strokes. or rather very broad strokes. Many of the global gradient parameters are already defined in sigmoid, addressing the two ends of the spectrum black and white, and some control of what happens in the middle, which is great. Then I saw the new color balance module, and had an aha moment, cos this is the kind of thing I had been thinking of, somewhat, but in my case, I’ve typically used curves, to adjust brightness, and gradient, in each region, manually, in the absence of other suitable modules.
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Regional - Next level would be the 4 regions, I described (or 3 for those who prefer), the superhighlight region is my own creative largesse. Shadows, Mid tones, Highlights, Superhighlights. The color balance rgb module, hints at using these regions to adjust the brightness (i.e the luminosity) in each of the regions, but its primary purpose is colour and it does not yet have anything for controlling the gradient within each region. My proposal for sigmoid, fundamentally speaks only to gradient, i.e contrast, either globally or regionally.
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Granularly - Like Tone EQ. It is a great module, but for broader changes, the crossover points between the regions are a bit “sticky”, and its not easy to pick the transition points, you want, exactly. The best you can do it pick the nearest region. So its close enough but not close enough. Using it to achieve what I had described needs compromises. Its also somewhat impossible like with curves, to avoid longitudinal movement of the transition points, i.e if I boost brightness in mid-tones, but I do not want any change in shadows, its hard if not impossible to achieve in Tone EQ. Tone EQ is a wonderful tool, but a bit too granular, for what I had described. As an aside, not wishing to derail this thread, but a good place to mention it here, I would wish for someday, a Tone EQ that has options for 16 levels, like the Ansel Adams thing. And of course to still have the option to only use 8 regions as we have today. I do not thing Sigmoid should be as granular as Tone-EQ, in its adjustment of gradient, cos that would be a bit too much, and be like a plane that is difficult to fly - way too delicate controls, and too many of them.
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Super granular - the most flexible tool we have now is the rgb curve where you can do whatever you like with gradients, but the flexibility comes at a price, not a very efficient tool - I have memories of spending days hand-creating my own curves with base curve, when that was all we had, back in the day. Filmic and Sigmoid, do a much more efficient job than anything one could create manually in rgb curve.
So if sigmoid could provide the regional gradient control, similar to what I have described, in addition to the global gradient control which it already provides, that would be christmas come early.