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Color corrections LAB or RAW

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  #1  
Old 07-25-2011, 03:28 PM
bart1986 bart1986 is offline
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Color corrections LAB or RAW

I'm reading the Dan Margulis LAB book and there's one little thing that i find odd. Dan makes an entire chapter about color correction in LAB, but what are the advantages compared to doing it in the RAW converter? Which happens to be non-destructive?

Are there advantages to doing it in LAB or is the book slightly out-dated on this subject?

Sorry if my english is messed up, its not my native language.

Thank!
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  #2  
Old 07-25-2011, 03:56 PM
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John Wheeler John Wheeler is offline
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Re: Color corrections LAB or RAW

Hallo Bart en ik geloof dat je uit België. Is uw taal het Nederlands, Frans of Duits? Ik neem een gok dat het Nederlands is. Welkom bij ReTouchPro. (Courtesy Google translate).

The tools available are rarely a one vs the other choice. Personally, I find the tools in Photoshop ACR or Adobe Lightroom quite robust, intuitive for the photographer and not only are you working with the original RAW files non-destructively, you can open them in Photoshop as a Smart Object so you can go back to the RAW file and make additional edits. I opt to make most of my changes with ACR or Lightroom, take them into Photoshop as Smart Objects and if still desired, use the techniques available in Lab Color Mode/Space.

LAB has many parallels to learning a new language. Tough at first yet when mastered, it is another tool that opens up possibilities and new ways to communicate not always possible in other languages. LAB's color mode/space (some would call it a religion) is another paradigm of how to get your work done. Whether it has benefit for any one person's situation/workflow I believe is decided individually. I personally appreciate having the LAB avenue available yet find that I use it sparingly. For others, I am sure it is a key part of their workflow. All of course IMHO
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Old 07-25-2011, 05:05 PM
bart1986 bart1986 is offline
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Re: Color corrections LAB or RAW

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Originally Posted by John Wheeler View Post
Hallo Bart en ik geloof dat je uit België. Is uw taal het Nederlands, Frans of Duits? Ik neem een gok dat het Nederlands is. Welkom bij ReTouchPro. (Courtesy Google translate).

The tools available are rarely a one vs the other choice. Personally, I find the tools in Photoshop ACR or Adobe Lightroom quite robust, intuitive for the photographer and not only are you working with the original RAW files non-destructively, you can open them in Photoshop as a Smart Object so you can go back to the RAW file and make additional edits. I opt to make most of my changes with ACR or Lightroom, take them into Photoshop as Smart Objects and if still desired, use the techniques available in Lab Color Mode/Space.

LAB has many parallels to learning a new language. Tough at first yet when mastered, it is another tool that opens up possibilities and new ways to communicate not always possible in other languages. LAB's color mode/space (some would call it a religion) is another paradigm of how to get your work done. Whether it has benefit for any one person's situation/workflow I believe is decided individually. I personally appreciate having the LAB avenue available yet find that I use it sparingly. For others, I am sure it is a key part of their workflow. All of course IMHO
Thanks! It always amazes me how badly the google translate thing works. You might as well just take some words from the dictionary, put them in a random order and type that lol. Anyhow, yes i speak Dutch.

So you are looking at it from a personal taste, and your taste is more towards RAW. But lets say you don't have a personal taste, are there any real benefits to doing it completely in LAB, stuff you can't possibly do in RAW and what is it?
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Old 07-25-2011, 05:24 PM
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Tony W Tony W is offline
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Re: Color corrections LAB or RAW

IMO, RAW should be your first stop to maximising image quality. As it is non destructive this is a huge benefit. Once you have gone as far as you are able in RAW then consider further work in Photoshop. Think carefully about the image and if it will benefit from LAB specifically - the canyon scenario from Dans book for instance or gross changes to colour. Can you achieve the same in RGB which will save a trip in and out of colour spaces - you will likely have to convert after LAB for your output device!

I think overall Dans books are excellent (if a little hard going at times) but he does seem to dismiss other options too easily at times. From memory ACR is one of those.

I cannot think of a benefit of ignoring RAW and going straight to LAB unless the image type absolutely demands it.
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Old 07-25-2011, 06:01 PM
bart1986 bart1986 is offline
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Re: Color corrections LAB or RAW

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Originally Posted by Tony W View Post
IMO, RAW should be your first stop to maximising image quality. As it is non destructive this is a huge benefit. Once you have gone as far as you are able in RAW then consider further work in Photoshop. Think carefully about the image and if it will benefit from LAB specifically - the canyon scenario from Dans book for instance or gross changes to colour. Can you achieve the same in RGB which will save a trip in and out of colour spaces - you will likely have to convert after LAB for your output device!

I think overall Dans books are excellent (if a little hard going at times) but he does seem to dismiss other options too easily at times. From memory ACR is one of those.

I cannot think of a benefit of ignoring RAW and going straight to LAB unless the image type absolutely demands it.
So is this something about the book being out-dated? Were there any RAW possibilities at the time the book was written? Because seriously after reading the first 5 chapters i am like, i can do this with photoshop/ACR and get the same results. Apart from the little thing he does in chapter one where he just makes a slight curve adjustment in the A&B channel in LAB mode which is quick, but again, can be done with PS. It's basically getting the colors to pop which you might as well do with a layer set to hue, take a foreground of 100% hue and a back of 100% de-saturation and start painting with different opacities.
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Old 07-25-2011, 07:49 PM
RobertAsh RobertAsh is offline
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Re: Color corrections LAB or RAW

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Originally Posted by bart1986 View Post
So is this something about the book being out-dated? Were there any RAW possibilities at the time the book was written? Because seriously after reading the first 5 chapters i am like, i can do this with photoshop/ACR and get the same results. .
The book is not outdated. And sometimes you can't always get the same results, certainly not nearly so easily (at least for me personally). That's one of the benefits of Lab color.


That said, Lightroom and ACR do incorporate Lab color already, to some degree, at least approximately:
  • The color balance sliders (Temp and Tint) in the white balance section manipulate the B channel (Temp = yellow / blue slider) and the A channel (Tint = magenta / green slider)
  • The Exposure / Brightness sliders and the tone curve manipulate the L channel.
But effectively you're limited to one set of L-a-b curves (one curves layer) with no masking.

So Dan's book is not obsolete but there are now ways to do similar things through different means. But of course - that's Photoshop for you

Last edited by RobertAsh; 07-25-2011 at 11:47 PM.
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Old 07-26-2011, 12:03 AM
RobertAsh RobertAsh is offline
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Re: Color corrections LAB or RAW

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...But effectively you're limited to one set of L-a-b curves (one curves layer) with no masking....
And even this functionality that I shared above in Lightroom and Adobe Camera Raw is, at best, "a poor man's Lab color." It has pretty stark limitations:
  • You can't manipulate Lab curves for the colors (A and B channels in Lab). The sliders induce or reduce color casts for basic white balance. If you think about the curves layers in Photoshop, the Temp and Tint sliders only allow you the equivalent of moving one point on the A or B channel up or down.
  • You can't stack layers. In Photoshop you can stack multiple Lab curves adjustment layers. Can't do that in LR or ACR.
  • You can't do selective application. Sliding the Temp or Tint sliders affects the entire image.
One strong upside to using LR or ACR is the Vibrance slider. Lab mode in Photoshop does not support the Vibrance adjustment layer. Would be great if Adobe made that happen in the next release of Photoshop.

So Dan's book is still very much on track, and which technique to use, or whether to use Lab or not, depends on your needs and working style.

There is a section in his book where he compares the strengths and weaknesses of all 3 major color spaces (RGB, CMYK, Lab). It's well done. Also, he cites on example where in a class of his a participant did best him in a challenge to do some technique in RGB. He said that was educational. So he's open to at least some degree to learning and to acknowledging the limitations of what is after all a human tool.

But for me, Lab has enabled me to do things I couldn't do before, and has enabled me to do things much more easily, more intuitively and faster than I could do in RGB. Nowadays I use Lab for landscapes and travel and RGB for portraits, and CMYK for skin tone color correction when I have a tough color cast I'm trying to eliminate, or (learned this from Dan's book) when there's some shadow detail I want to extract that I can't do in either of the other color spaces (that's rare but it's happened).
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  #8  
Old 07-26-2011, 12:20 AM
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D Thompson D Thompson is offline
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Re: Color corrections LAB or RAW

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Originally Posted by RobertAsh View Post
Nowadays I use Lab for landscapes and travel and RGB for portraits, and CMYK for skin tone color correction when I have a tough color cast I'm trying to eliminate...
Do you go from one to another and then back again? Ex. - start out in RGB, switch to CMYK for some correction, and then back to RGB. Is there any harm doing that. I usually stay in RGB, but will change the sampler readout to CMYK at times.
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Old 07-26-2011, 04:15 AM
RobertAsh RobertAsh is offline
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Re: Color corrections LAB or RAW

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Originally Posted by DWThomp View Post
Do you go from one to another and then back again? Ex. - start out in RGB, switch to CMYK for some correction, and then back to RGB. Is there any harm doing that. I usually stay in RGB, but will change the sampler readout to CMYK at times.
Sometimes I do. I often start out in Lightroom which uses an RGB variant. If I like something I do there, I'll move into Photoshop and convert profile to Lab color.

No harm done in moving between color spaces that I've personally encountered. The one problem is that when you change color spaces you lose all your adjustment layers in the previous color space and can't re-trace your steps (or you have to save multiple copies of the file, one for each color space). Making it into a Smart Object should work to avoid that, but for me it that doesn't work.

So I'll either save a different copy of the file or, more often, will do:
  • Image>Duplicate,
  • Convert the duplicate to the other color space (e.g. CMYK)and work in the other color space.
  • Convert the duplicate back to my original color space (e.g., Lab) and flatten or Merge Visible.
  • Drag the resulting layer into my original file as a new layer.
Gets tricky but it's manageable when the need is there.
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Old 07-26-2011, 09:50 AM
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Tony W Tony W is offline
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Re: Color corrections LAB or RAW

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Originally Posted by bart1986 View Post
So is this something about the book being out-dated? Were there any RAW possibilities at the time the book was written? Because seriously after reading the first 5 chapters i am like, i can do this with photoshop/ACR and get the same results. Apart from the little thing he does in chapter one where he just makes a slight curve adjustment in the A&B channel in LAB mode which is quick, but again, can be done with PS. It's basically getting the colors to pop which you might as well do with a layer set to hue, take a foreground of 100% hue and a back of 100% de-saturation and start painting with different opacities.
The information given in the books is not outdated IMO. He is presenting different ways to reach your final goals.

ACR was around at the time he wrote the book no idea which version. As far as I remember he spent no time in ACR and gave the impression that he dismissed it as not being valuable. On the other hand somewhere he did say that RAW converters were coming of age and a hotly fought for area. So I suspect that his opinion may have changed to date?

Only you will be able to decide which method to make colours pop. In my view LAB is capable of doing a quicker and possibly better job in most cirumstances.

Here are Dans opinions from Professional Photoshop fifth edition 2007 on LAB
  • Excellent for quick correction when no time for fine tuning
  • Best sharpening space for images not dominated by one colour
  • Allows cost free blurring of colour noise
  • Easy to eliminate gross colour casts
  • Steepening the A dn B is the most natural looking way of creating colour variation or more intense colours
If your image falls within any of the above categories then perhaps you should consider LAB as an option. Even so I would still want to assess and take the image as far as possible first in ACR. AFAIK any RAW capture you make will open first in Photoshop via the Camera RAW module (not aware if you can turn this off) so why would you not take advantage of this first?
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