Using Basic Tone VS. Tone Curve to adjust Photos?

[southwestform]

After adjusting exposure, highlights, shadows, whites, and blacks, I achieve what I consider to be nice contrast.

1. Why would I now need to adjust my RGB curve to increase brightness/contrast with single points or with an S -Curve? Is this essentially doing the same thing as what I did previously? Is it just another way of doing basic exposure/contrast to an image?

2. Does it make sense to skip over the Basic Tone sliders and just do everything with the RGB curve in the Tone Curve panel?

Thanks.

[JP Hess]

As I see it, the tone curve adjustment is there and available when/if you just can't quite achieve what is needed with the basic adjustments. Sometimes I find I can get a much more pleasing effect with an S curve. Not always, but sometimes.

[southwestform]

So is it correct to say that the Tone Curve is technically doing the same thing as the basic adjustment sliders? Just curious because I'm trying to understand the overall workflow when editing.

Thanks.

[JP Hess]

Basically, I think that is true. However, it's possible to be much more precise in making tonal adjustments using the tone curve in one finds it necessary to do so. Whether or not you find it beneficial or not is something you will have to evaluate for yourself. I have only begun to use the tone curve more frequently in recent weeks. It's something I think you'll just have to experiment with and decide.

[ManiacJoe]

I would say that the two are doing similar things in slightly different ways.

If I need to use both adjustments, I will always to the tone curve first. I even have a few dev presets just for that.

I tend to see the tone curve as a "large adjustment" tool, while the Basic panel as more of a "small adjustment" tool. Keep in mind that this is probably more of a personal mindset than an accurate description of the tools.

[Conrad C]

southwestform  wrote

So is it correct to say that the Tone Curve is technically doing the same thing as the basic adjustment sliders?

No, because the Basic controls and the Tone Curve are different and somewhat complementary approaches to the same problem.

While the traditional Tone Curve has been a great workhorse for 30 years, it does nothing more than take a certain channel input value like 120 and output it to a different value like 117. That's all that happens at any point in the Tone Curve. A specific value is shifted up or down. That's it.

The Basic controls are newer, more sophisticated, and overcome the limitations of the Tone Curve. Most Basic controls do not simply take a value and shift it. Of the Basic controls, I think Contrast, Whites, and Blacks are probably the ones that could easily replaced by Tone Curve moves. But not the others.

The Highlights control applies processing that does things like try to reconstruct blown highlights in one channel by looking at highlight information in the other channels. Shadows also uses advanced techniques; it creates a mask to protect non-shadow tones (unlike the Tone Curve, where boosting shadows often reduces contrast too much in other ranges), and it applies additional processing to enhance shadow detail. You are not going to be able to use the Tone Curve to reproduce what Highlights and Shadows can do.

Clarity and Dehaze are other examples. Clarity is a midtone contrast adjustment; that part could be done with a Tone Curve. But Clarity is also said to be “image-adaptive” and I think it also involves additional processing that tries to keep the contrast boost confined along edges, while suppressing halos at higher values.

Dehaze uses processing that involves a haze model that, according to Adobe, is "based on a physical model of how light is transmitted, and it tries to estimate light that is lost due to absorption and scattering through the atmosphere," so there's no way a Tone Curve could account for all that on its own.

Because the Tone Curve is older and simpler, it's placed after the Basic controls. Some like to teach that the Basic controls are so much more advanced that you no longer need to use the Tone Curve. I don’t agree...sometimes, what an image needs is a simple contrast adjustment within a specific range and the Tone Curve is still a quick, precise way to do that. I think the Basic controls are better at doing the majority of the work, and the Tone Curve should be brought in when an image needs the kind of contrast refinement that the Tone Curve best suited for. I end up using the Basic controls on all images, and the Tone Curve on maybe the 10-15% of images that need it.

[carolz25348614]

As you mentioned,

'The Highlights control applies processing that does things like try to reconstruct blown highlights in one channel by looking at highlight information in the other channels. Shadows also uses advanced techniques; it creates a mask to protect non-shadow tones (unlike the Tone Curve, where boosting shadows often reduces contrast too much in other ranges), and it applies additional processing to enhance shadow detail. '

Could you please explain what algorithm may involve in highlights and shadows sliders? How the mask generated? Thanks a lot.

[Conrad C]

carolz25348614  wrote

Could you please explain what algorithm may involve in highlights and shadows sliders? How the mask generated? Thanks a lot.

Sorry it took me so long to reply to your question. I was trying to remember what they were called. I finally did (Local Laplacian Filters), and that helped me find the Adobe blog post where I learned about some of this:

Lightroom Journal: Magic or Local Laplacian Filters?

That blog post contains links to the academic research papers that were the basis for the special handling of shadows and highlights.

[erudolph]

It seems to me that with the Tone Curve you can move the pivot point of an S-Curve.  Whereas using the Basic controls, while you can adjust contrast, you cannot move the center around which the contrast adjustment is taking place.

[Ian Lyons]

southwestform  wrote

After adjusting exposure, highlights, shadows, whites, and blacks, I achieve what I consider to be nice contrast.

1. Why would I now need to adjust my RGB curve to increase brightness/contrast with single points or with an S -Curve? Is this essentially doing the same thing as what I did previously? Is it just another way of doing basic exposure/contrast to an image?

2. Does it make sense to skip over the Basic Tone sliders and just do everything with the RGB curve in the Tone Curve panel?

Thanks.

As has already been pointed out, they both do 'similar' things. In terms of tonal adjustments you can think of the Basic panel as a kitchen knife and the Tone Curve as a surgeons scalpel. The Tone Curve also allows you to apply very fine colour adjustments to individual colour channels whereas the Basic panel has no way of fine tuning colour other than using White Balance.

I recommend finding a few difficult images in your collection then spending time editing these images with both Basic panel and Tone Curve.

[Earth Oliver]

Can anyone answer why we have 2 curves which are allowed to be non-similar? Are both being applied to my image? Why does the slider curve not reset to Linear when i specify, but the point curve does?