• Welcome to the Lightroom Queen Forums! We're a friendly bunch, so please feel free to register and join in the conversation. If you're not familiar with forums, you'll find step by step instructions on how to post your first thread under Help at the bottom of the page. You're also welcome to download our free Lightroom Quick Start eBooks and explore our other FAQ resources.
  • Stop struggling with Lightroom! There's no need to spend hours hunting for the answers to your Lightroom Classic questions. All the information you need is in Adobe Lightroom Classic - The Missing FAQ!

    To help you get started, there's a series of easy tutorials to guide you through a simple workflow. As you grow in confidence, the book switches to a conversational FAQ format, so you can quickly find answers to advanced questions. And better still, the eBooks are updated for every release, so it's always up to date.

Tone Curve Panel question

Joined
Jan 18, 2009
Messages
494
Location
Winnipeg, Canada
Lightroom Experience
Advanced
Lightroom Version
Classic
Lightroom Version
10.4
Operating System
  1. Windows 10
Hi there,
For adjusting tone in my images, I normally just drag the different areas of the Histogram. For me that is easy to understand and easy to do. I'm puzzled however, that changes made using the Histogram or using the Basic panel, are not reflected in the Tone Curve. Anyone know why that is?
 
Joined
Jan 18, 2009
Messages
494
Location
Winnipeg, Canada
Lightroom Experience
Advanced
Lightroom Version
Classic
Wow. Mac or PC? I'm on a PC and this question has bugged me for years. The Histogram and Basic Tone adjustments have no effect at all for me in the Tone Curve panel. Been that way through many iterations of Lightroom.
Thanks for letting me know.
 
Joined
Nov 27, 2013
Messages
1,673
Location
Queensland
Lightroom Experience
Intermediate
Lightroom Version
Classic
changes made using the Histogram or using the Basic panel, are not reflected in the Tone Curve.
Correct, and TBMK has always been that way.
I have understood that you can use either or both (Basic Sliders & Tone Curve) and the Tone Curve can be used to add 'finer nuances' to image tones 'added to..' the Basic slider adjustments.
Or, consider Basic sliders for 'beginners' and Tone Curve for 'advanced' tonal adjustments.
In the end it is the final appearance of you image that matters, not the journey to get there :)
 
Joined
Jul 2, 2015
Messages
11,502
Location
Netherlands
Lightroom Experience
Power User
Lightroom Version
I just checked and if I make changes using the histogram or using the sliders those changes do, in fact, show up in the Tone Curve.
I wonder which sliders you are referring to. The sliders in the Basic panel? No way. The sliders underneath the tone curve when it is used as a parametric curve? Of course.
 
Joined
Jan 18, 2009
Messages
494
Location
Winnipeg, Canada
Lightroom Experience
Advanced
Lightroom Version
Classic
To me they should all relate. We are adjusting tonal values.
The Histogram should reflect what the tones are no matter how they were adjusted
The Tone Curve should reflect what the tones are no matter how they were adjusted

Anything that affects tonal values, should be represented in ALL functions that represent and allow for the adjustment of tonal values. Adjusting a little here or a little there and not seeing it in the histogram makes no sense. Adjusting values using the Histogram or Tone Curve should relate to each other. Otherwise one or both are meaningless.
Really don't understand the programming logic behind this at all.

It's like having to have 3 different thermometers to take the temperature of bath water:
  1. For use when water is added using the tap
  2. For use when water is added using a kettle
  3. For use when water is added using a bucket
Can you imagine the frustration if all three thermometers gave different readings in the same water?

All methods result in temperature changes that should be reflected the same on all three thermometers.

Current system is abject silliness IMHO.
 

Colin Grant

Active Member
Joined
Apr 18, 2016
Messages
397
Location
Norfolk
Lightroom Experience
Intermediate
Lightroom Version
Classic
To me they should all relate. We are adjusting tonal values.
The Histogram should reflect what the tones are no matter how they were adjusted
The Tone Curve should reflect what the tones are no matter how they were adjusted

Anything that affects tonal values, should be represented in ALL functions that represent and allow for the adjustment of tonal values. Adjusting a little here or a little there and not seeing it in the histogram makes no sense. Adjusting values using the Histogram or Tone Curve should relate to each other. Otherwise one or both are meaningless.
Really don't understand the programming logic behind this at all.

It's like having to have 3 different thermometers to take the temperature of bath water:
  1. For use when water is added using the tap
  2. For use when water is added using a kettle
  3. For use when water is added using a bucket
Can you imagine the frustration if all three thermometers gave different readings in the same water?

All methods result in temperature changes that should be reflected the same on all three thermometers.

Current system is abject silliness IMHO.
Have to say I have never found it an inconvenience. I Just view the curve as another stand-alone adjustment tool. Trying to imagine how the tone curve would look if it worked as you would like hurts my brain so I have given up.
 
Joined
Nov 30, 2012
Messages
666
Lightroom Experience
Power User
Lightroom Version
Classic
I'm puzzled however, that changes made using the Histogram or using the Basic panel, are not reflected in the Tone Curve. Anyone know why that is?
Just to make sure I understand the problem…it sounds like this is not about the histogram graph updating behind the Histogram and Tone Curve controls, but about changes to one panel’s control set (not the tone graph) showing up in the other panel’s control set?

If so…it is all working as designed, and there is no reason why dragging the Histogram or changing Basic panel values should change the Tone Curve. It’s because they change the image using technically different methods. They should not reflect each other, because they aren't doing the same thing.

The Tone Curve is the old-style (e.g. Photoshop 1990) simple in/out value change. In other words, when you change a level on the Tone Curve, you’re saying something like “take value 56 from the image, and make it 67.” Find all pixels at a certain level, and change them by exactly the same number of levels. That’s it.

That is not what happens when you drag the Histogram or a Basic panel slider. Those two controls are tied together, and what they do is use newer, more intelligent algorithms that are somewhat aware of pixel context and content. For example, if you increase the Shadows value in the Basic panel or Histogram, it is not simply doing a uniform shift of the values of each pixel in that range. Shadows also does some shadow detail recovery, and importantly, it auto-masks shadow values to help isolate the edit and keep it from unintentionally affecting midtones and highlights as much as a similar edit in the Tone Curve would. Part of that involves analyzing nearby pixels to optimize local contrast, and as a result (and unlike the Tone Curve) some pixels of the same original value may change more than others. Similarly, Highlights can apply detail recovery of a clipped channel by analyzing data from non-clipped channels. The Tone Curve is too simple to reflect those types of non-uniform changes that may involve neighboring pixels and neighboring channels.

The Basic panel options also address a long-standing problem with the old Tone Curve: Increasing contrast in one curve segment must decrease it in another, which is not always what you want, or too much of a compromise. The Basic panel options are designed to isolate changes to the intended tonal range with far fewer compromises than the old Tone Curve, and that is one reason the Basic panel is above the Tone Curve.

But there are times when you need exactly what the Tone Curve does, so it still has a job to do. The Basic panel/Histogram drag sometimes doesn’t give you enough control over contrast within a specific narrow tonal range. So for example after I’m done with Basic panel adjustments, if I just want a little more snap near but not exactly at the midtones, I’ll steepen the Tone Curve just there. In this case, a Tone Curve edit is used to refine the Basic panel edits.

So the Basic panel/Histogram and the Tone Curve are provide two technically different approaches to tonal distribution, and because of that, they should not or cannot reflect each other’s changes. And that is a great feature (not a bug), because when used together, they can do more for you than each can do separately.

By the way, there is also a similar perception out there about all of the color panels. It seems like a fair number of users think that White Balance, HSL, Color Grading, and Calibration are different front ends to the same color math so they stick to the one they like to use, but that is also not true; all of them affect color quite differently.
 
Joined
Jul 2, 2015
Messages
11,502
Location
Netherlands
Lightroom Experience
Power User
Lightroom Version
The Histogram should reflect what the tones are no matter how they were adjusted
The Tone Curve should reflect what the tones are no matter how they were adjusted
The histogram does show you what the tones are, no matter how they were adjusted.

The tone curve is not a curve that shows you the current state of the tones, but a tool that allows you to change that state. That is why the tone curve should not change from linear to something else if you change the tones with another tool. I do not know any image editor that does that with its tone curve and to me it would make zero sense if it did.
 
Joined
Jan 18, 2009
Messages
494
Location
Winnipeg, Canada
Lightroom Experience
Advanced
Lightroom Version
Classic
Thanks for the replies guys. I think I can see what you mean and the reasoning. I'm still puzzled as to why EVERY tonal adjustment in any panel, affects the image and the Histogram, but that only works partially in reverse.
  • Adjustments to the Histogram are reflected in the image and the Basic panel but nothing else
  • Adjustments to the Tone Curve panel are reflected in the image and the Histogram but nothing else
  • Adjustments to the HSL or B&W panels are reflected in the image and the Histogram but nothing else
  • Adjustments to the Color Grading panel are reflected in the image and the Histogram but nothing else
The Histogram reflects all tonal adjustments. So to me ..adjusting it, should have some affect on all the adjustment that feed it.

To me its still the water and thermometers in the bathtub thing. I appreciate and accept your explanations as informative on why it is the way it is, and won't bother you to explain it any further, but will still harbor my non-programmer's opinion.

Perhaps the bottom line is "Fiddle with everything until you think it looks good"?

Cheers!
 
Joined
Jul 2, 2015
Messages
11,502
Location
Netherlands
Lightroom Experience
Power User
Lightroom Version
Thanks for the replies guys. I think I can see what you mean and the reasoning. I'm still puzzled as to why EVERY tonal adjustment in any panel, affects the image and the Histogram, but that only works partially in reverse
The vice versa explanation is simple. You cannot really ‘adjust the histogram’. The histogram is the image, just shown in a different way. Yes, Lightroom has a feature where you can drag in the histogram to make adjustments, but that is just something Adobe did as an alternative for moving certain sliders. A nice interface gimmick. That means they linked histogram-dragging to some sliders, and not to other sliders or to the tone curve. In most, if not all, other image editors you cannot drag in the histogram at all.
 
Joined
Nov 30, 2012
Messages
666
Lightroom Experience
Power User
Lightroom Version
Classic
Right. If you apply Johan's explanation, the list reduces down more simply:
  • Each panel (other than the Histogram) provides its own unique set of adjustments. No panel alters values in any other panel.
  • The reason the Histogram is excluded from the previous point is that all it does is graph the cumulative new tonal distribution resulting from the adjustments in all panels. (There is a layer of draggable controls over the Histogram, but that’s explained next.)
  • The Histogram does not have its own unique set of options that is reflected in Basic Tone options. The draggable controls overlaid on the Histogram are simply the same Basic Tone options presented through an alternate interface. When you drag within the Histogram, the draggable control layer over the Histogram is divided into tonal ranges, and each of those ranges corresponds to a specific Basic Tone panel option. As you drag within the Histogram, you can see which tonal range is highlighted on it as you also watch that range’s corresponding Basic Tone panel option update.
So, it is not so much that “Histogram adjustments are reflected in the Basic Tone panel,” it’s more that “making adjustments by dragging the control layer over the Histogram is the same as dragging sliders in the Basic Tone panel,” and as it is with all panels, the Histogram interactively updates to account for the changes.

It’s a subtle difference, but it’s the key to understanding the whole thing and simplifying the model of how it works.
 
Top