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Author Topic: Contrast Adjustment slider  (Read 5070 times)

One Frame at a Time

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Contrast Adjustment slider
« on: July 11, 2012, 04:29:53 pm »

Hi,  when I was working in PS I was taught not to use the Contrast Adjustment.  My memory for this is a little hazy, but the reason was something about Contrast Adjustment "throwing away data" due to compression of the images tone range.  More accuracy and less loss was achieved by using Curves.  Now that I am in LR I was wondering if this same school of thought applied?  

Thanks,

Paul
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jrsforums

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Re: Contrast Adjustment slider
« Reply #1 on: July 11, 2012, 04:43:09 pm »

No, but you can use curves if you prefer.
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Schewe

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Re: Contrast Adjustment slider
« Reply #2 on: July 11, 2012, 05:46:40 pm »

Now that I am in LR I was wondering if this same school of thought applied?  

No...not at all. In fact much of what people "think" about processing in Photoshop doesn't apply at all in LR & ACR because regardless of how or when you make an adjustment, the actual processing pipeline does it's own optimized processing order. In point of fact, the Contrast slider in LR with PV 2012 s a pretty important tool to use. That's why it's second after Exposure...
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One Frame at a Time

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Re: Contrast Adjustment slider
« Reply #3 on: July 12, 2012, 12:06:36 pm »

Thanks - thats great!
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digitaldog

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Re: Contrast Adjustment slider
« Reply #4 on: July 12, 2012, 12:20:05 pm »

In the old days, within Photoshop, Contrast and Brightness were looked down upon because there were a linear correction. IOW, you shifted all tones in one direction. In modern versions of Photoshop, that isn’t the case unless you click on the “use legacy” check box. But as Jeff points out, this is all vastly different in LR anyway. So any comments about Contrast from old time Photoshop users doesn’t apply in LR/ACR and probably doesn’t apply in Photoshop much either, unless you have the legacy check box on. And, it can be useful to use the legacy behavior from time to time, especially on masks/alpha channels.
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wolfnowl

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Re: Contrast Adjustment slider
« Reply #5 on: July 12, 2012, 02:57:20 pm »

No...not at all. In fact much of what people "think" about processing in Photoshop doesn't apply at all in LR & ACR because regardless of how or when you make an adjustment, the actual processing pipeline does it's own optimized processing order. In point of fact, the Contrast slider in LR with PV 2012 s a pretty important tool to use. That's why it's second after Exposure...

Forgive me for being dense, but aren't that statement and this one different? (emphasis mine)

The issue is that you are adjusting the sliders out of order, e.g., you were adjusting Highlights/Shadows even though Whites/Blacks had already been adjusted (e.g., Whites +60).  The sliders are generally arranged so that the later sliders depend on the earlier ones, e.g., the range and methods used to implement Whites/Blacks depends on what you've set Highlights/Shadows to.  Thus I suggest (generally) editing top-down.

Not trying to be difficult, just trying to learn and understand.

Mike.
« Last Edit: July 12, 2012, 02:58:54 pm by wolfnowl »
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Tony Jay

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Re: Contrast Adjustment slider
« Reply #6 on: July 12, 2012, 04:19:17 pm »

Actually what both these gentlemen are saying is absolutely true and should not be regarded as in opposition but rather complementing the other.

Lr will optimize whatever adjustments are made and in whatever order, however that does not mean that one should take a laissez faire approach to using sliders for tonal manipulation in Lr since process 2012 is designed to be used in a top-down order.
It is better to manipulate exposure and contrast before moving on to the other sliders.
BTW just because some of the sliders have the same names as those used in Lr3 (AKA process 2010) does not mean that they work in the same way in Lr4 (AKA process 2012).

Regards

Tony Jay
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Schewe

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Re: Contrast Adjustment slider
« Reply #7 on: July 12, 2012, 06:01:16 pm »

Yeah, what Tony said...

In Photoshop, the order you do something in has an impact and Contrast was a heavy handed approach that only dealt with contrast. In PS, curves could do both contrast AND color at once so it was abetter option. In ACR/LR the processing pipeline is fixed into it's own order and nothing a user may do will alter that...

What Eric is saying is that when making adjustments, it's optimal to do them in a top down order for ease and efficiency...that has nothing to do with the order in which ACR/LR will actually process them. Don't mix up the two...
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wolfnowl

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Re: Contrast Adjustment slider
« Reply #8 on: July 13, 2012, 01:56:30 am »

Thanks for the clarification!

Mike.
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One Frame at a Time

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Re: Contrast Adjustment slider
« Reply #9 on: July 15, 2012, 11:29:35 pm »

Another related question:  I'm finding myself jumping down to the Clarity adjustment early in my workflow.  I usually keep the setting under 15.  Clarity always improves the image but affects the tonal adjustments in a way that requires readjusting  tones following the prescribed order.  Using clarity early seems to speed the process.  Am i committing a serious error?  If so, can you explain why?  Thanks!!
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Tony Jay

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Re: Contrast Adjustment slider
« Reply #10 on: July 16, 2012, 12:09:52 am »

Making major adjustments in the top-down order suggested does not proscribe one from subsequently fine tuning tonal adjustments.
The effect of clarity adjustments will normally only affect the black and white points so only fine adjustments with the whites and blacks sliders will normally be all that is required.
Sometimes using tone curve adjustments will also be useful.

As already noted when the image is rendered and the tonal editing is "hardwired" into the image the processing engine optimizes the rendering process.

Regards

Tony Jay
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