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What's so great looking about the S curve in color grading?

When it comes to grading, I can't figure out why so many people use this look in their movies. It has sort of a grindhouse look to it, and I am not really sure what the appeal is, especially since so many movies don't seem to use it.

What is it that makes it so popular among colorists, I was just curious?
 
A logarithmic colour space makes better use of the available dit depth in order to capture a greater tonal range.

Basically, it uses a logarithmic curve to compress the dynamic range. It more closely mimics the response of film emulsion.

It's not intended for viewing, it's intended for capture. You then colour grade it to get the desired look. It's simply a way to capture more tonal information (more steps which essentially equates to more dynamic range).

You therefore have more control in the grade as to how you 'place' the colours and the exposure.

If it's ever used as a viewing space, it's usually because either the director/client/editor has spent so long watching it being cut in log gamma that they become used to seeing it that way, or they don't want to get rid of the dynamic range that they've been able to capture. That's why it can be good to deliver proxy rushes with a LUT applied - so the editor and Director don't have to guess what it's going to look like, and you can provide the originals/'raw' files to the colourist when it comes time to do the grade and online.
 
Oh so you are saying that the S curve should be applied in shooting, before post then?

Hmm... Perhaps I'm confused... I assume you mean logarithmic colour space?

If you mean curves as part of the grading process... Well, that's just a choice I guess. Curves are an important and useful tool; if you mean things like crushed blacks and strange gamma that seems to be the rage on low budget, DSLR films then I agree.

That's not necessarily an 's' though
 
ohoh, this could be a babylonian thread ;)

@H44 if you post examples we all see what you are talking about :)

(PS.
@Jax your inbox is full. I wondered if you got my message a while back)
 
The S-curve you are talking about, when done correctly, "restores" the proper levels of the image.

Generally most digital camera's we use today, as Jax was talking about, shoot a flatter image to capture maximum dynamic range. So when you get back into the color correcting phase in post, you apply a subtle S-curve to bring the blacks and whites back into the image for a realistic look.

Your comment about it having a "grindhouse look" makes me think you are just applying too drastic of an S-curve. It should be very subtle.
 
Okay thanks. I tried to make the s curve very subtle though.

Here is a before an after example. The first photo is shot without the s curve, in camera. The second photo is done with the s curve, plus a little more contrast I added. It seems that it looks kind of like a bit of a grindhouse look, at least to me. What do you think?

https://youtu.be/BoI6sMS0RdA
 
Firstly that example isn't very subtle at all. You've crushed too much detail out of your blacks.
Secondly, the s-curve is only part of the equation. For my tastes that image is over-saturated, and the colour balance is wrong. Your subject is also lit very unflatteringly, contributing to your grindhouse (ie low budget) aesthetic.
 
Okay thanks.

I didn't add any saturation in the image. Making the s curve alone adds saturation to it, it seems. So if I make the s curve, should I then desaturate after? The only other thing I added in the image is contrast. Here is the image with the contrast taken out and the only change made to the original, is the s curve itself. The s curve I did is shown at the end of the video.

https://youtu.be/jKIWfP65FtM

Did I make too much of an s curve and I need to make it more subtle? Cause I didn't really push it much at all, or so I thought.

Also, is the saturation and contrast too much in the second example, since adjusting the s curve also increases both it seems? Also when you say the color balance is wrong, in what way? I shot under fluorescent lights, white balanced to the lights, and then in post I added a little blue for a certain look I was going for. I removed it in this new current video. But is that what you meant? Was it the blue added in post, that made the color balance seem off?
 
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How do you know you shot without s curve?
In a Canon DSLR a little curve is always applied to pictures, unless you set the curve to flat in the raw editor. (Providing you shot RAW pictures)

You said it yourself: you added an s curve AND contrast.
Adding contrast makes images look more saturated.
Applying a S curve makes an image look more contrasty.
So you did 2 things to increase contrast, while you want to compare 1 thing. Where is the logic in that?
BTW, how did you add the contrast?

You might think you didn't overdo a curve, but it is smarter to look at the image you create with it.
The image dictates whether or not a curve is too heavy, not the shape of the curve.
 
Okay thanks, I see your point about the contrast. In the second example video, the contrast is removed, and just the s curve is applied.

I applied the contrast before, by increasing the 'contrast' as it's called in Premiere Pro. Now the contrast is not applied at all in the second video.

The s curve is still adding saturation on it's own though.

If the camera is already applying enough of an s curve, is an s curve in post necessary then?

If I should remove the s curve in the camera, how does one do that with an Canon DSLR?
 
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I applied the contrast before, by increasing the 'contrast' as it's called in Premiere Pro. Now the contrast is not applied at all in the second video.
It has been said before: don't use the contrast effect in Premiere. I provides little control and you don't know what you are doing while moving the slider.
I repeat: NEVER use the contrast effect. I tis close to useless.
Better use color wheels, levels or curves to control contrast.


The s curve is still adding saturation on it's own though.
Because you influence the contrast in the image, you influence the saturation.
REMEMBER THIS: contrast is NOT the name of an effect. Contrast is a concept to discus the amount of 'opposite values' in an image/sound/story/whatever: small vs big, black vs white, treble vs bass, loud vs silent, empthe vs. crouded, and so on. (Affinity is the opposite of contrast.)
Applying an s curve pulls shadows down and raises highlights while the lowest and highest values can stay the same (unless you move those end points).

If the camera is already applying enough of an s curve, is an s curve in post necessary then?
If the image from the camera is they way you want it, you indeed don't have to do anything with it.
That is what I was referring to: you need to look at the image, understand scopes and waveforms, calibrate your monitor with a real tool, and understand the tools to manipulate the image to be able to change it in a way you actually get what you want.
Just applying a S curve because you read that that is the way to go, you are making up dogmatic rules again. Rules you aren't supposed to make anymore, right?
Never* do something, because it is a rule, but because it helps to get the image you want.
(* This applies to filmmaking only. Don't break rules in traffic, unless following the rules will kill/hurt you or someone else. Don't break the law or you'll be in trouble. The same goes with breaking promises to your spouse :P )

So: you your eyes and brain.

If I should remove the s curve in the camera, how does one do that with an Canon DSLR?

Have you ever tried to take a picture with a Canon?
Did you ever shoot a picture in the RAW format?
Did you ever open a RAW picture (you know .cr2-file) in Photoshop?
Did you ever see the menu on the right for the curves?
Did you ever look at it?
Did you ever notice that in raw file the standard setting is a 'normal contrast' and that you can also choose 'lineair contrast' (or something like that) and 'high contrast'?
Choose the lineair one. This shows the RAW photograph without S curve applied to it.
(I would appreciate it if you quoted this list and replied to every question. Otherwise nobody but you (??) will understand whether you understand what I say here.)

One does not remove s curve in a Canon, one can only lower contrast. Which is the closest you can get.


Recap in short:
s curve is not the holy grail to get a great looking image.
It is just something that is used for footage shot in a certain way to get a certain look or basic look to work from.
 
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Okay thanks. I won't use that contrast anymore. But if I use the contrast in curves, it also crushes the blacks just as much. From now on, I can apply the s curve first, and then contrast with curves second, if that's better.

I don't have to use the s curve. I was just expirementing with it, since it seems to be so popular among other filmmakers in their color grading. So I was asking what is so special about it, since just applying it, even a little, looks kind of grindhouse-ish to me.

As for taking RAW pictures, my Canon DSLR will only allow me to do that with still pictures. I cannot shoot RAW video. So in that case, can I still not have the s curve in video, if I cannot shoot RAW?

As far as coming up with my own look and using my eyes, I have come up with a look. It doesn't use the s curve. Mainly my look is to push the blacks and shadows in curves just a little, as well as highlighting the midtones a little. Then I add a little blue and cyan accordingly, for some of the looks I am going for.

My eyes tell me that is the way to go, as far as what I have come up with for my own looks.
 
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As for taking RAW pictures, my Canon DSLR will only allow me to do that with still pictures. I cannot shoot RAW video.
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Yes, I was talking about pictures so you can see what I try to tell you. That is why I refer to the RAW editor in Photoshop.
I know Canon DSLR only shoot RAW pictures.
I've been using them since before the time they could shoot video.
 
Okay thanks. But what is the point of using RAW pictures to learn to grade, since I am trying to figure out how to color grade video, and will not be able to apply the same options?

LEARN TO READ.

I'm not saying you should learn how to grade RAW picture.
I'm telling you to shoot a RAW picture, open the file in the Photoshop RAW editor, go to the curves tab on the right and see how the standard setting is using a mild S curve, change it to lineair to see how it looks without s-curve. And then set it to heavy contrast to see how it looks with a strong s curve. (there are a few settings you can choose, so that makes it easy to see how it effects the image.)

Observing this might help you to understand how s curve changes contrast.

You can even play with the curve if you want.
The only difference is that RAW picture can take heavier manipulations than H264 video. (And yes, you can't use the RAWeditor). But the CONCEPT of how a S curve changes contrast (and saturation) is the same.

If you would just once do what is suggested, instead of only reading it and saying 'okay thanks' you would have learnt a lot more by now. Reading does not always equal learning. Some things need to be experienced to make sense.
 
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