# Contrast and saturation relationship



## Yorg (Aug 6, 2014)

There's something I don't understand.
Why does colour saturation go up when contrast is adjusted?
From my old analog days - I am just getting into digital, and my avenue to the new world is largely LR - raising contrast was essentially to steepen the slope of the tone curve.
In LR, you can change the 'contrast' slider, but the curve remains the same.
As you change the curve or the contrast slider, the saturation changes.
I don't get this.
From my understanding the contrast should go up, but the colour shouldn't shift.
Can anyone help me understand this?


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## davidedric (Aug 8, 2014)

I'm expecting one of the gurus to reply sometime, but a couple of comments from my more limited perspective. 

It also seems to me a little odd that the tone curve doesn't appear to change when you move the contrast slider,  though obviously you are adjusting the tone mapping.   With your experience, have you tried manipulating the tone curve directly?   In the Tone panel you will find a Targeted Adjustment Tool (TAT).   If you select this and move it over the image to the area where you wish to increase contrast,  it will show you exactly which part of the curve you need to steepen. 

As I understand it,  many of sliders in Lightroom are adaptive -  their exact effect is image dependent -  which may be why we see quite complex results when we move them. 

Now,  hopefully over to the experts! 

Dave


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## Victoria Bampton (Aug 8, 2014)

Have a read of this article: http://ptgmedia.pearsoncmg.com/imprint_downloads/peachpit/peachpit/lightroom4/pdf_files/LRCurves.pdf  There's some good info from Thomas Knoll (who wrote the ACR engine)


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## Tony Jay (Aug 10, 2014)

Check this out as well:www.luminous-landscape.com/essays/Curves.shtml 
It is written by Mark Segal and also compares the tone curves in Lightroom and Photoshop.

Tony Jay


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## LouieSherwin (Aug 10, 2014)

Interesting reading. One thing to keep in mind is that Lightroom (and ACR) use a process pipeline to apply all the adjustments to each image. This means that the order of the adjustments is always the same regardless of order that you move the individual sliders. This also means that the Contrast slider and the Curves panel are two completely separate adjustments in the Lightroom pipeline and by using one or the other or both together you can achieve different results.

With the release of PV2012 it is my understanding is that the old PV2010 defaults with the bump in the Brightness and Contrast are now "baked" into the default settings. I find I can get much more pleasing results by essentially removing those settings by using a starting point of -1.0 exposure and -33 contrast as my default. Then using Whites and Blacks to set tonal range of the image and finally using the point curve to set the overall contrast. (Please see Michael Frye's excellent video tutorial Lightroom 4: The New Tone Controls for more on this subject). Mostly the resulting bump in saturation is in keeping with overall image adjustments and brings a richness and depth to the image that I cannot get otherwise. Sometimes, however, at times the saturation is too much and I simply reduce the global saturation slider as needed.  

-louie


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## Yorg (Aug 12, 2014)

I'll try that LS.


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