Primary adjustments with Tone EQ

[pedrorrodriguez]

This previous issue still applies:

#134

In addition, currently the UI of the Tone EQ module is mostly geared towards secondary adjustments. If one tries to make primary ones, things get awkward. Here are a couple of thoughts:

• An adjustable histogram is not useful for primary adjustment. Having a way to set white and black levels would be faster to set up and easier to understand than posterization, exposure and contrast compensation.
• 9 nodes are more than what's needed for primary adjustment. 5 would be enough. The right- and leftmost nodes would control white and black levels respectively. The middle one, midtones. The remaining two, highlights and shadows.
• Curve smoothness adjustment is perhaps also not needed. Primary adjustments are broad and smooth.

[pedrorrodriguez]

For primary and secondary adjustments use two instances of tone EQ with different curve smoothing, so that the first is very broad, and the second very precise.