Saturation Transform -- New Mask defaults to 50% gray

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den
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Saturation Transform -- New Mask defaults to 50% gray

Post by den »

Ref: PWP8 Beta 7-May-2019

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
Saturation Transform.jpg (60.16 KiB) Viewed 2875 times
...den...
jsachs
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Re: Saturation Transform -- New Mask defaults to 50% gray

Post by jsachs »

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.
Jonathan Sachs
Digital Light & Color
den
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Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: Saturation Transform -- New Mask defaults to 50% gray

Post by den »

...
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
Saturation Transform 2.jpg (27.67 KiB) Viewed 2868 times
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jsachs
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Re: Saturation Transform -- New Mask defaults to 50% gray

Post by jsachs »

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.
Jonathan Sachs
Digital Light & Color
den
Posts: 856
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: Saturation Transform -- New Mask defaults to 50% gray

Post by den »

OK... ...Thank you.

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.

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jsachs
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Re: Saturation Transform -- New Mask defaults to 50% gray

Post by jsachs »

PWP7 works exactly the same way.
Jonathan Sachs
Digital Light & Color
den
Posts: 856
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: Saturation Transform -- New Mask defaults to 50% gray

Post by den »

Agree... but:

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.

...den...
den
Posts: 856
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: Saturation Transform -- New Mask defaults to 50% gray

Post by den »

Added illustrations...
PWP8's Saturation Amount mask using the same settings will only have a 50 to 100% Gray tone range
HSV-S Map with Saturation-New Mask.jpg
HSV-S Map with Saturation-New Mask.jpg (59.58 KiB) Viewed 2837 times
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PWP8 Masks transform with the same settings you will have a mask with 0 to 100% Gray tones
HSV-S Map with Masks-Mask 1.jpg
HSV-S Map with Masks-Mask 1.jpg (57.32 KiB) Viewed 2837 times
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...den...
jsachs
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Joined: January 22nd, 2009, 11:03 pm

Re: Saturation Transform -- New Mask defaults to 50% gray

Post by jsachs »

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.
Jonathan Sachs
Digital Light & Color
jsachs
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Joined: January 22nd, 2009, 11:03 pm

Re: Saturation Transform -- New Mask defaults to 50% gray

Post by jsachs »

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.
Jonathan Sachs
Digital Light & Color
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