Setting dynamic range end points: Two methods and two questions

I learned to set the dynamic range end points in Photoshop by setting the high/low clipping indicators and moving the end points of the Tone Curve until clipping started.

The same thing can be done in PL by the same method. In addition, the same can be achieved using the Highlights and Blacks sliders in Selective tones.

Two questions: Is the any advantage of one method over the other? I’ve tried both methods and see no differences. What’s the point of resetting the end points? I’ve read it recovers a portion of “wasted” dynamic range. But, if a photo is naturally grey and washed out (think of a foggy ocean vista), recovering the range will unnaturally raise the contrast.

While results might look alike under certain conditions, the two methods you describe don’t do the same. Have a look at the following histograms:


A selective tone slider does not influence the whole tonal range (hence it’s called selective tones) while shifting the endpoints of the tone curve does. Similar result, but still different…

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Thank you for the explanation.

What kind of image did you use to get that histogram?

It’s an image I made in Photoshop. I call it “Crazy Grey”, see what it looks like:

The strips go from 0 to 255 in 18 steps and are simply mirrored, stacked and surrounded by a medium grey border. The center cross is black and white with a medium grey dot in the middle.

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Assuming the image has room on the right side in the histogram, what might be the difference between the slider and exposure compensation? In raw.
I never could find much difference but I didn’t try it with “Crazey Grey”.

George

As you can see in the histograms above, selective tone changes compress brighter tones. Changing the white and black points in the histogram tool does not do that. Both methods can clip black and white tones though.

Note that both histograms don’t show the original crazy grey histogram. They show results from changes using the two methods mentioned above.

I mean exposure compensation vs white point.

George

Platypus,

What a great learning device! It enables the visualization of the effects of tools. I’ve been playing with it for an hour. Some tools are linear, some non-linear, some clip, some limit clipping. I’m getting a much better understanding of PL and the smarter use of it. Thank you.

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Hello Platypus, hello all

I put the crazy grey to my test pictures, many thanks.
There are some test pictures under https://monochrom.com/farbmanagement-icc-profilservice in the section " Testbilder - Druckerprofil überprüfen"
That’s the ones I used the last years for tests

best regards