When selecting a New mask with the Saturation transform, the mask background defaults to a 50% gray rather than having expected black/white image areas with preference black to gray transitions when settings are made...
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Saturation Transform.jpg (60.16 KiB) Viewed 3615 times
That's intentional because the Saturation Amount control is zero-centered -- gray does nothing, lighter than gray increases saturation, darker than gray decreases saturation. Same with the Brightness transformation.
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Try this...
1) Open an image, select New mask.
2) Use the Mask Rectangle tool to mask half the image... ...results in a mask half 50% gray and half white.
3) Move the White Amount slider from 0 to +100%... ...notice that there is an increase of saturation in the 50% gray image area as well as the exaggerated increase white image areas...
4) The only way to not make saturation changes in the 50% gray image area is to move the Black slider to -100%.
This makes the mask formulation for this transform unique from other transforms using masks and different from previous PWP8 releases. Perhaps the documentation should be updated?
Transformations.pdf --- Saturation:
Saturation Transform 2.jpg (27.67 KiB) Viewed 3608 times
First, Saturation is not unique -- the other transformation that works this way is Brightness. These transformations are unique in that they let you light and darken or saturate and desaturate at the same time.
I oversimplified when I said no change where the mask is gray -- it's no change when the Amount is 50%. With a single slider, this happens when the slider is in the middle.
When you make the mask half gray and half white and then set the black slider to 0 and the white slider to 100, gray is now at 75, so part of the gray area becomes more saturated. This is just like other transformations where moving the double sliders changes the amounts assigned to different mask gray levels. To preserve gray as 50, you need to keep the black and white sliders equidistant from the center. Or you can use the half-mask buttons to set half the mask to black and half to white and then set the black slider to 50.
I can visualized what is happening and what's needed to make a preference mask and adjustment. This does not seem to be as intuitive as PWP7's Saturation/Mask but does have increased nuance saturation adjustment potential.
A PWP7 Amount mask will have a 0 to 100% Gray tone range but PWP8's Saturation Amount mask using the same settings will only have a 50 to 100% Gray tone range or 0 to 50% Gray tone range.
If you use PWP8 Masks transform with the same settings you will have a mask with 0 to 100% Gray tones same as PWP7's.
The "50 to 100% Gray tone range or 0 to 50% Gray tone range" of PWP8's Saturation transform masks is what was confusing me.
This is because the Saturation mask starts off with a 50% gray everywhere while Masks starts off with a 0% black mask. The Add mode combines the curve with the current mask. If you want to make them look the same, click the button to make the mask black when you start making your Saturation mask.
This thread is making me think the initial mask should always be black, even for zero-centered Amount controls since the double sliders control the amount range anyway.