Skin tones with Premiere/FCPX/Resolve

[Don Kotlos]

http://menexmachina.blogspot.com/2018/07/skin-tones-with-premierefcpxresolve.html

[Cary Knoop]

32 minutes ago, Don Kotlos said:

While exposure, contrast, curves in Lumetri color panel suffer from this, the classic old style Brightness & Contrast Effect in Premiere behaves the same as FCPX and adjusts levels by shifting all channels with an additive term. This results to better skin tones, so if you want to adjust contrast or reduce exposure in Premiere you should use this effect and avoid using the exposure/contrast/curves in Lumetri color panel.

I partly agree and partly disagree.

I agree that the Exposure slider in the Lumetri panel is not good (although I think things have improved somewhat in CC2017) and I would agree to generally avoid this slider altogether. I disagree with you about the Contrast slider. This slider is the classic s-curve and in my opinion works just fine! 

The Contrast slider in the Lumetri panel is very dissimilar to the Contrast from the Brightness & Contrast effect (or the ProcAmp effect), it fact it affects the dynamic range of an image not the contrast. 

I think the Curves in the Lumetri panel are just fine and operate as expected, I really do not understand on what grounds you base your criticism of Curves.  In fact you can completely copy the Brightness & Contrast operations with curves!

In addition I think the Color Wheels in the Lumetri panel are very good as well.

 

[Don Kotlos]

16 minutes ago, Cary Knoop said:

I partly agree and partly disagree.

I agree that the Exposure slider in the Lumetri panel is not good (although I think things have improved somewhat in CC2017) and I would agree to generally avoid this slider altogether. I disagree with you about the Contrast slider. This slider is the classic s-curve and in my opinion works just fine! 

The Contrast slider in the Lumetri panel is very dissimilar to the Contrast from the Brightness & Contrast effect (or the ProcAmp effect), it fact it affects the dynamic range of an image not the contrast. 

I think the Curves in the Lumetri panel are just fine and operate as expected, I really do not understand on what grounds you base your criticism of Curves.  

Adjusting contrast with either the slider or the curves in Lumetri panel changes the hues of skin tones! Not the way it is expected to work at all. The effect is the same as with the exposure example that I have posted. 

If you compare it to the curves/contrast of Resolve it becomes really obvious. 

[Cary Knoop]

4 minutes ago, Don Kotlos said:

Adjusting contrast with either the slider or the curves in Lumetri panel changes the hues of skin tones! Not the way it is expected at all.

I am sorry but that is simply not true, just watch the vector scope!  Saturation (obviously) changes but hue does not!

By the way, and you probably know this already, if you want to guard against saturation changes (although it can obviously not be totally prevented) you could do your modifications in an adjustment layer with a Luminosity blend mode.

 

[Don Kotlos]

3 minutes ago, Cary Knoop said:

I am sorry but that is simply not true, just watch the vector scope!  Saturation (obviously) changes but hue does not! 

It is true. Maybe its hard for you to see in this small size but the vector scope also shows a difference. 

[Cary Knoop]

27 minutes ago, Don Kotlos said:

It is true. Maybe its hard for you to see in this small size but the vector scope also shows a difference. 

Here is a video comparing the two NLE's.  As you can see curves do not change hue both for Premiere Pro and Resolve.

 

 

[Don Kotlos]

14 minutes ago, Cary Knoop said:

Here is a video comparing the two NLE's.  As you can see curves do not change hue both for Premiere Pro and Resolve.

Here I made it easier for you to see:

 

 

 

[Cary Knoop]

16 minutes ago, Don Kotlos said:

Here I made it easier for you to see:

 

 

 

Going that extreme I would no longer define as color correcting, I think that is doing something very wrong with a video.

But alright now please do the same extreme curves in Resolve.

I stand by the video!

 

[Don Kotlos]

2 minutes ago, Cary Knoop said:

Going that extreme I would no longer define as color correcting, I think that is doing something very wrong with a video.

But alright now please do the same extreme curves in Resolve.

Now how did I know you are going to say this? 

I offer a subtle grade and you close your eyes, I make it extreme just so you can see and you don't like it because it does not agree with what you are claiming.  

If you actually look at the picture that I posted at the top you are going to see that Resolve does not change hue whereas Premiere with Lumetri color does.

But its fine if you don't like the comparison (or the result), I am not going to argue with you any more.

Maybe this thread is not for you, but for people that are (too) sensitive to differences in skin tones. 

[Cary Knoop]

I presume a similar example will not be shown with Resolve.  At any rate I made one:

 

[Axel]

5 hours ago, Don Kotlos said:

Long story short, if you want to achieve the best skin tones grade in Resolve. But I guess most of you already knew that right?  

I could follow you. Without knowing the background, that is how contrast and exposure are being computed and relate to colors, I came to the same conclusion. Thanks.

[no_connection]

I don't get what you are after.

Gain and exposure is not the same ting.(unless you are working in linear space) And clipping always change hue.

[Don Kotlos]

17 minutes ago, no_connection said:

Gain and exposure is not the same ting.(unless you are working in linear space) And clipping always change hue.

Of course not since cameras have their own calibration, but if you want to adjust the how bright/dark a scene is in Resolve you have to use gain. 

The point of this post is about changes in hues that occur even with no clipping in Premiere Lumetri color panel when adjusting either the exposure/contrast/curves. 

[no_connection]

To compare apples to apple you have to change exposure in Resolve too.

You can by converting Rec to linear, change gain, then back to Rec. Or change whatever nonlinear space you are working with into linear and back again.