LR Tools, which ones do you use?

[davidedric]

Just to add to the discussion, my understanding from reading Jeff Schewe's "The Digital Negative" is that there is a fundamental difference between the operation of all of the sliders and the curves. The sliders are "image adaptive" - in other words, the changes that they make are dependent on the image in question, whereas the curve adjustments are not. (I don't think he means in the trivial sense that all images are different, so the effects most differ). I'll have to re-read it to get my head round it again.

Dave

[Mike Buckley]

The sliders are "image adaptive" - in other words, the changes that they make are dependent on the image in question, whereas the curve adjustments are not.

I wonder if I understand you correctly. In theory, if I could create the exact same curve using the sliders or using the curve points, are you saying that the results would not be the same when applied to the same image? Similarly, if I applied the exact same curve using the sliders to two very different images, are you saying that the tones would be remapped differently because the two images are so different?

[davidedric]

I may be getting out of my depth here

As best I understand it, the tonal regions affected by the sliders are image dependent. Schewe's workflow is to start with the sliders, and fine tune with the curves. So, no, I don't think the results would be different depending on how you produced the tone curve.

I think it is hard to know, though, because after adjusting tones with the sliders, the curves panel still shows a straight line,. I don't know how to see the curve that would have been produced by the sliders changes.

Confused of Cheshire

[Mike Buckley]

after adjusting tones with the sliders, the curves panel still shows a straight line

Mark also mentioned that and I don't understand it. As an example, when I move any slider in the Curve panel, the curve changes as I move it. Moreover, I can't imagine wanting to adjust the curve if I wasn't able to see both the changes made to the image and the changes made to the curve.

I wonder if the changes are immediately evident on my system because perhaps the panel is in a particular mode that might be different from whatever mode you and Mark are describing. I don't see any evidence of modes for that panel other than changing from using the sliders to using the curve points. I'm completely stumped about this.

[NorthernFocus]

...I can produce virtually an infinite number of curves using the points that simply cannot be produced using the sliders....

I guess that depends on one's definition of "virtually" infinite. By definition the curves adjustments still requires digital therefore discreet adjustments so there is a finite combination of possible changes. There are four sliders that go from +100 to -100. That equates to over 1.5 million possible combinations for a given image (ignoring the "adaptive" nature). There may be people out there with eyes good enough to discern that many variations. I am not one of them. So to me that's a "virtually infinite" number of adjustments.

And just to be further anal on the topic facts are demonstrable. With the information available to us, how can one state definitively that the same curve could not be duplicated with one of the million some odd combinations of slider combinations? The only true comparison would be to overlay the output histograms. I doubt it's important to any of us to go to that level of effort to prove a point so we're off into a purely theoretical discussion now, aren't we....

For the record, I hate the slider format for the tools. As pointed out by someone further down in this thread, the cool thing in the current rev of LR is that you can put the cursor directly on the histogram and manipulate it without ever looking at the sliders. So similar to the curves concept, if you want more detail in a given part of the histo, you stretch it out. Comparable to increasing the slope of the curve over that same part of the input histogram.

Also for the record, I do use the tone curve. But I use it as intended by the program designers, in addition to, not in lieu of the sliders/histogram manipulation. I find it really useful when highlights/shadows still lack contrast after manipulating the histogram/sliders. You can give either end a bit of a kick with the curve.

Interestingly, the one tool that I'm using less and less is the clarity. When I first started using LR I thought it was pretty cool. But the more detailed I get, the less I like it.

Some of the above goes with the caveat that the "knowledgeable individuals" who provide LR training know what the heck they are talking about when they describe what's "under the hood".

[NorthernFocus]

...after adjusting tones with the sliders, the curves panel still shows a straight line...

As I understand it, the tools do not independently work on the input values. Once you make adjustments in the "basic" panel, all of the other tools are additive on top of that. So the curve tool is starting with the output of the previous adjustments as its straight line reference. Which is really cool. As I said, not intended to use one or the other but rather one in addition to the other.

[Mike Buckley]

Great comments, Dan!

I gather from your response to David about his thinking that the Curves panel remains a straight line after adjusting tones with the sliders that he and Mark are referring to sliders that are not in the Curves panel. That makes sense to me and clears up my earlier confusion. I was thinking they were saying that moving sliders in the Curves panel didn't produce a change in the curve.

[Mike Buckley]

I constructed the curve shown below in about 30 seconds using curve points. If it's possible to construct anything remotely close to that curve using the sliders, please do and show it to us.

I realize that the curve that I constructed is extreme and would surely never be used to impact an entire image. I doubt that it would ever be applied even to part of an image using software that makes doing so possible. However, if Lightroom ever provides the possibility of applying a curve to part of an image, part of my purpose for participating in this aspect of the discussion is that I have applied curves to parts of images that could not have been produced using Lightroom's sliders.

'Nuff said.

[Downrigger]

Great comments, Dan!

I gather from your response to David about his thinking that the Curves panel remains a straight line after adjusting tones with the sliders that he and Mark are referring to sliders that are not in the Curves panel. That makes sense to me and clears up my earlier confusion. I was thinking they were saying that moving sliders in the Curves panel didn't produce a change in the curve.

Exactly - there are sliders for "highlights" "shadows" "whites" and blacks" in the basic panel - you cannot adjust the luminosity ranges over which these each apply. You can move the white point and black point of the histogram back and forth using the respective sliders, and for all four the overall the main effect is to move the curve wholesale to the right or left. Whatever one does, the curve in the tone curve panel remains the same straight line. Subsequently directly altering the curve in the tone curve panel superimposes input/output adjustments onto the changes already made with the four basic panel sliders.

[NorthernFocus]

I constructed the curve shown below in about 30 seconds using curve points. If it's possible to construct anything remotely close to that curve using the sliders, please do and show it to us.

I realize that the curve that I constructed is extreme and would surely never be used to impact an entire image. I doubt that it would ever be applied even to part of an image using software that makes doing so possible. However, if Lightroom ever provides the possibility of applying a curve to part of an image, part of my purpose for participating in this aspect of the discussion is that I have applied curves to parts of images that could not have been produced using Lightroom's sliders.

'Nuff said.

Then again, maybe Adobe's intent with the sliders tool is to protect us from ourselves....

[Mike Buckley]

Whatever one does [using adjustments in the Basic panel], the curve in the tone curve panel remains the same straight line.

That's appropriate, as Dan mentioned. That's because the Curve tool maps all pixels of a certain luminosity to a different luminosity and you would not want the curve displayed in the Curve tool constantly changing. Instead, you want it to be straight at the point in time that you begin working with it and you want it to remain as you left it once you had made your final curve adjustment no matter what other changes you later make to the image.

The curve begins with a straight line before adjusting it because the input values (the beginning luminosity values) represented on the X-axis and the corresponding output values (the changed luminosity values) represented on the Y-axis are the same. Thus, connecting the dots between all 256 values where the X-axis and Y-axis meet forms a straight line. Once you map at least one input value to a different output value, connecting all of the dots where the X-axis and Y-axis meet no longer forms a perfectly straight line.

[davidedric]

Thanks to those on the other side of the pond, who have resolved my confusion while I slept. I was indeed referring to the sliders in the Basic Panel (as was the quote from Jeff Schewe). I can see the logic behind how it works, but it might also be good to be able to see the Basic sliders' tone changes mapped on to a tone curve, to use as a basis for further tweaking. Very interesting discussion though.

Dave

[Mike Buckley]

it might also be good to be able to see the Basic sliders' tone changes mapped on to a tone curve, to use as a basis for further tweaking.

That's essentially the role the histogram plays in my workflow. We should always be keeping an eye on it as we make changes.