A New Article For Digital Photo Pro Magazine: Tone Curves …

by George on October 14, 2013

Photograph © George A. Jardine

A new article for you on the Tone Curve has just been published in Digital Photo Pro magazine.

Writing articles for Digital Photo Pro Magazine is one of my favorite things to do. You can find this one, and a complete list of all my free videos, and articles that I’ve written for various publications at the bottom of my “free stuff” page, by clicking here.

{ 13 comments… read them below or add one }

Duane Pandorf October 14, 2013 at 1:22 PM

Thanks for sharing this George. Its a great refresher from your video series!

Class A October 19, 2013 at 10:37 PM

Well-written, George, and thanks for sharing.

I do believe, however, that you did not really answer the question as to what is fundamentally different between the basic panel controls vs the tone curve controls. I’m sure many users wonder which adjustment challenge asks for which of those two tools.

When you use the “Highlights” and “Shadows” sliders of the basic control panel, you are also changing both brightness (of certain tonal values) and contrast (the difference to other tonal values) at the same time.

I suspect — I haven’t investigated this at all so far because PV 2012 has been irrelevant to me to this date — that the basic control panel sliders imply the use of image masks so that the overall effect — in particular in the transition areas between affected and unaffected tonal values — is different compared to using the tone curve.

However, this is just speculation and I could be completely wrong. It is unfortunate that Adobe is not more forthcoming about what is under the hood of the basic panel controls.

One thing is for sure: With the tone curve, you are in complete control where your adjustments begin and end, e.g., where your highlight boost starts and your shadow darkening stops. With the basic panel controls, your a passenger of Adobe’s “I’m trying to be smart and do lots of adaptive stuff and auto ranging, auto recovery and what not”-policy that I find unhelpful for people who know what they are doing. As dumb as I am, I’m still smarter than Adobe’s “clever” algorithms. “Smart” software can be convenient for simple cases, but when things become a little bit more tricky, I find you are fighting its inappropriate assumptions rather than it supporting you.

If there is anyone who could shed more light on the issue of when it is better to use the basic panel controls vs the tone curve, it would be you George. I hope you’ll investigate this further.

George October 20, 2013 at 9:20 AM

Thanks for your comments (“Class A”), and I’m glad you enjoyed the article.

To your question, “what is fundamentally different between the basic panel controls vs the tone curve controls”… I can only say that from my POV this is a very complicated question, not easily or accurately answered by anyone other than probably 3 or 4 engineers who work on the code. (Some of the usual suspects try, of course, but I still find their writing on the subject to be off, and somewhat superficial.) I could stick my neck out and say that the fundamental difference between them is that the Basic Tone Controls are adjusting the algorithm used during the tone-mapping of the data from the de-mosaiced, gamma 1.0 space, to the internal working space which is in something more like gamma 2.2. And the Tone Curve is working on the post tone-mapped data. But that’s the way I have come to understand it, and the reality would probably be better explained by someone such as Eric Chan.

But anyway… who would that help? So that’s why I hesitate to say.

If you watch my free videos on the subject (and even reading this online article), I think you’ll find that when I speak in terms of “how the controls work” it is always to the end of trying to help you make better pictures. And in that vein, I try to show how I think the basic tone-mapping works in this video, and how simply moving exposure up and down can affect not only brightness, but contrast, in various zones. And in my video on the 2012 Process controls I do go on at length about how certain controls enhance edge-definition as they do their job of “recovering” highlights or shadow detail.

In the end, you might be right that a more distilled and precise explanation of exactly how the controls are different would be useful…. to a tiny, tiny group of photographers. But I worked for a year on the tone-mapping video, and very few people seem to get it or respond to the information in that video. Why? Because videos that show them “how to make their pictures look better” are vastly more accessible.

So for now, I’m sticking with the more practical, without ending up selling $.99 hamburgers.


Class A October 21, 2013 at 10:28 PM

Hi George,

thanks a lot for your very honest reply. Thanks a lot as well for all the pointers.

I understand your position. I’m not sure myself how “tiny” the group of photographers would be that would benefit from a systematic understanding of the LR controls.

Look, you could say, “Just play with the sliders of the parametric tone curve controls, or move points on the point curve controls around until you like the image. Here is what roughly happens when you do things…”. The above would be fine in terms of “making pictures look better (somehow)”. However, you find it useful to point out what the effect (e.g., in terms of tonal contrast) of certain actions is. I believe you find it useful to mention the cause->effect relationships because they take the guesswork out of using the controls.

The less we understand controls (e.g., the basic panel controls), the more guesswork is involved. Yes, the incredibly powerful learner that is your brain — with a lot of experience — will be able to somewhat predict effects. But the less orthogonal the effect of a set of controls is, the harder it is to gain the experience, and the more likely it is that you’ll run into a situation where all your previous experience with the sliders fails you.

I personally — I may well be in a “tiny, tiny group” — for instance find it terrible that apparently three LR sliders affect highlight recovery. This, and other non-orthogonal controls, means that I cannot set one slider right to never touch it again, but that I pretty much always have to go back and forth between sliders, revisiting my temporary choices, until I find a kind of equilibrium. This is
a) slow, and
b) unsatisfactory, because I can never quite be sure whether I just hit a local maximum or really found the best set of settings for what I’m after. Had a chosen a different ordering of using the sliders, I would probably have ended up with a different result. This is not good.

Yes, with a lot of experience, you can get faster and you learn how to avoid some of the local maxima, but you are not really mastering the controls unless you have a pretty good idea about what exactly it is what they do.

Adobe’s design decisions are of course not your fault. And I realise that even the best understanding will require me to revisit earlier slider choices from time to time. I also fully understand the importance of visual feedback and that ultimately the artistic impression counts, not any scientifically correct settings. But I’m still unhappy with LR/Adobe leaving me so much in the dark as to how to use their controls *systematically*. That’s why I commented.

I appreciate that it may not be in your best interest to only pursue the “most systematic approach” route.

Thanks again for your educational work and your response.

George October 22, 2013 at 7:57 AM

Probably the single most important lesson that I learned working with Hamburg and the Lightroom team during the development of the new product, is that power comes with complexity. Sure, as our engineering and interface designs evolve over generations and generations of software, we do slowly learn how to make more powerful software that is less complicated. But raw photo processing is still (I believe) in its infancy. Given that, having a requirement that imagines a set of controls to be “orthogonal” to the effect sounds a little like pie-in-the-sky to me.

Anyway, almost every other instructor tries to create a “systematic” method of correction, even if that means simply parroting what they hear from engineers who attempt to satisfy the request by saying “start from the top”. Nearly every instructor that I am aware of, aside from Dan Ballard. Dan’s approach is by far the least “educated” and “systematic” that I’ve seen, and his corrections are also among the best.

Class A October 23, 2013 at 7:03 AM

There is nothing pie-in-the-sky about avoiding unnecessary non-orthogonality. As a matter of fact, PV 2012 tries to achieve orthogonality in terms of tonal isolation and succeeds at that far better than PV 2010.

However, PV 2012 also comes with the attitude that the engineers know what photographers want so you cannot change the whole exposure of the image anymore without a “film-like” roll-off whether you want it or not. And you cannot reduce brighter tones anymore without automatically invoking some highlight recovery. This latter “feature” — intended to make editing more convenient (or even idiot-proof?) has caused some people who want to deliberately blow out their backgrounds some grief. Why not give users the option to opt-out of “auto recovery”, “auto-black” and “auto-what-not”? I highly suspect because it would complicate the interface.

I do not believe that a systematic interface needs to be complicated. It would be less of an “auto pilot” experience, though. But an “auto-pilot” behaviour seems what Adobe wants to provide.

I don’t belong to the kind of people who want their software to make their decision for them. And I believe a lot of people are moving sliders back and forth in long-winded sessions because they are fighting Adobe’s “smart” approach.

I’m happy for users to enjoy an auto-compression of highlights when they increase exposure, if it works for them. The problem is, one cannot opt out of that scheme and has to move multiple sliders to achieve a simple linear boost across all tones. Now, if I have to move multiple sliders to achieve simple things, I’d at least like to know what these sliders do and how they differ from tone curve controls.

This has nothing to do with simple “start from the top” approaches. “Systematic” is not synonymous with “schematic”. Let’s refer to what I’m after as “informed” editing.

If you only roughly know what a control does and roughly know when to use it as opposed to another one, well then you are only roughly informed. Surely one can edit that way, but AFAIC, it is not the most effective way.

George Jardine October 23, 2013 at 4:49 PM

For you, I recommend Aperture, or Capture 1.

John Woodman November 18, 2013 at 1:15 PM

George – I found this the most helpful article so far on how the tone curve controls affect work, and I’m truly grateful. My problem is that I struggle to see where the contrast needs to be added to an image. I can watch your videos, and see the difference that you are making with the controls. But how do you identify where the adjustments need to be made. For me it is just trial and error. If you can point me towards anything helpful, I would appreciate it.

George November 18, 2013 at 1:40 PM

Hi John,

Glad you liked the article. Yeah…. for the most part, it is… a “visual process”. You might call that ‘trial and error’. But when it comes to being able to pre-visualize the difference between the contrast you drive through the midtones with a move on the Lights portion of the curve, vs the contrast you lose in the same tones by using Darks…. I would call that a visual process. The image on screen is the feedback, that guides your hand.

On the other hand, in the Lightroom Develop video #6 (on the Tone Curve), I try to show how as you’re working with a correction, you can sometimes see exactly what needs to happen next. We work on a landscape in Tibet where you come to a point where you can see that you need to expand (and darken!) the highlight tones all the way from the middle to the top, by pulling the curve down, all through the midtones.

So, I guess you might call it a combination of practice, and… trial and error. :-) But anyway, I think that’s a good way to think about it, rather than looking for “rules”. Which unfortunately, are a dime a dozen out there in the morass of online videos.

Hope that helps,

John Woodman November 19, 2013 at 2:34 AM

Thanks, George. I assume this is video #6 in the Masterclass series – I’ve been saving these up until I felt stronger. I’ll watch it now, and maybe get back to you.

George November 19, 2013 at 6:51 AM

No, actually, I meant 5 & 6 from the regular Develop series. The Tone Curve videos:



Brian Powell March 30, 2014 at 8:33 PM

Every year I shoot the fashion show and most of the day is on my isolated-on-white set (where I WANT to blow out the white background and tileboard flooring, etc.). Many other times I need the white BG to stay pure white (for product photography mostly).

Is there any way to opt-out of how Lightroom ‘recovers’ highlights and changes my photos from pure white to some kind of super light grey density?

I found the forums where users suggest this, as MANY times us working pros NEED a pure white background in camera and in post. All the suggestions are just global adjustments that affect BOTH the subject and background. (duh). Nothing else on the web seems to answer this ‘feature’.

Why hasn’t Adobe made this simple change? Should be an optional feature IMO.Give pros control over basic things like this.

My only recourse seems to be reverting to 2003 Process in the camera calibration dialog — which I hate to do because the look definitely changes and adds work to my flow. Not sure what else happens there, but using a process from 2003 is unsettling.


George March 30, 2014 at 9:06 PM

I’m confused. Asking for a way to “opt-out of how Lightroom recovers highlights”, and a local adjustment that only affects the background and not the subject are two different things.

“Why hasn’t Adobe made this simple change?”

Do you mean why haven’t they added a one-button white background clean-up function? Probably because doing that well is going to be a much harder engineering task than you might imagine. Besides, there are many easy ways to set an appropriate white point in Lightroom, or using Photoshop’s many selection and masking tools once in RGB.

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