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Is Lab color (L*a*b*) still relevant?

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  #11  
Old 04-23-2015, 12:33 AM
creativeretouch creativeretouch is offline
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Re: Is Lab color (L*a*b*) still relevant?

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Originally Posted by andrewrodney View Post
Using RGB as a correction space gives the user access to three color channels not available in Lab, so what?
Better results? That's what needs to be proven. Personally I believe you'll get better results, faster, with less data loss using parametric edits from raw data. That's kind of, sort of has three color channels too, and gives the user access to three color channels not available in Lab.
Color selection/separation tools in Lab work much precisely - from my experience - for example you can create better masks in Lab and it is also much faster.
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  #12  
Old 04-23-2015, 01:13 AM
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Aladdin Aladdin is offline
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Re: Is Lab color (L*a*b*) still relevant?

I think what @Shoku meant to state is that, LAB has two color channels and luminosity channel, this is what gives it its power, working with pure color. There are host of examples as why LAB is powerful, it is really very simple mode to work in if you give it a chance. Just like any other tool, no magic there, you just have to attempt to understand it to appreciate it.

- You can easily sharpen an image in the L channel without affecting the the color (over saturation) in the A & B channels. No halos either.

- You can manipulate colors without affecting contrast. The opposite is true.

- Massive control over color -> B&W conversion

- Perform D&B on the L channel without the nasty saturation you would get under RGB, because we are not touching the color in the A&B channels.


- Easily and accurately perform color replacement, even those colors you can't touch under RGB (color replacement even affects the tiny and faint specs of color that RGB cant touch, you get real true color replacement since it is done in the A&B channels only, not affecting brightness or contrast, you get very smooth transition).

Dog,
LAP is not a fad, not workaround, not hard to understand, I do not know why people are intimidated by it, just like any other tool, you have to exert the effort to get to know it and achieve results. The reason we don't see much of it in tutorials is that, people love short cuts. Period.

Please search the name Dan Margulis, he is the LAB master.
Please watch this 5 minute intro, it will answer all your questions: http://kelbyone.com/course/cs3_lab/

Then look up the Man from Mars technique by Dan, here is an example
https://www.ledet.com/margulis/Maker..._from_Mars.pdf or here: https://www.youtube.com/watch?v=vS53pAS0RqQ

There is video on the Mars subject by Dan himself, try to find it.

This one is very useful, it illustrates few things, it also explains what Lab is, I strongly recommend if you watch it: https://www.youtube.com/watch?v=KhfRynutmQM

Last edited by Aladdin; 04-23-2015 at 01:40 AM.
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  #13  
Old 04-23-2015, 09:02 AM
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andrewrodney andrewrodney is offline
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Re: Is Lab color (L*a*b*) still relevant?

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Originally Posted by Aladdin View Post
- You can easily sharpen an image in the L channel without affecting the the color (over saturation) in the A & B channels. No halos either.

- You can manipulate colors without affecting contrast. The opposite is true.

- Massive control over color -> B&W conversion
True in RGB as well if you use the Luminosity blend mode/fade control. And virtually all of the above can be done on raw data, before a true RGB file that could be converted to Lab is even possible.
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  #14  
Old 04-23-2015, 09:42 AM
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Doug Nelson Doug Nelson is offline
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Re: Is Lab color (L*a*b*) still relevant?

That's an interesting thought. Is raw responsible for the decline of Lab usage?
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  #15  
Old 04-23-2015, 09:52 AM
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Re: Is Lab color (L*a*b*) still relevant?

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Originally Posted by Doug Nelson View Post
That's an interesting thought. Is raw responsible for the decline of Lab usage?
Perhaps. The question is, where's the best place to do the work? Good old Dan M. was a master of taking awful rendered images he was supplied and fixing them in Photoshop. He didn't have a clue about photography or raw processing.

I know people in these parts are still provided awful rendered images and have to make lemonade out of lemons and Dan's teachings still apply. But speaking for myself, I'm a photographer, only capture raw (outside of the iPhone) and I wouldn’t think of producing the butt ugly images we see in Dan's Lab book (yes I own it). So it depends.

It would be useful to know how many non photographers here who retouch are provided a raw file instead of a questionably decent rendered image. Or if they get a poorly rendered image if they could get the raw and start from scratch.

It's like getting a good film scan versus a really bad one. Which would you rather start work on? I submit that if given a raw, with a good raw processor, 95% +/- of the Lab work done in PS would be unnecessary, at least for global color and tone work.
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  #16  
Old 04-23-2015, 10:16 AM
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Doug Nelson Doug Nelson is offline
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Re: Is Lab color (L*a*b*) still relevant?

Someone should invite Dan over here, I think he'd fit right in.
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  #17  
Old 04-23-2015, 10:46 AM
skoobey skoobey is offline
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Re: Is Lab color (L*a*b*) still relevant?

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Originally Posted by andrewrodney View Post
It's like getting a good film scan versus a really bad one. Which would you rather start work on? I submit that if given a raw, with a good raw processor, 95% +/- of the Lab work done in PS would be unnecessary, at least for global color and tone work.
Which is probably why I don't use it even though I am aware of it.

EDIT: I was wondering who Dan was, found out in the meantime. Don't quite see anything new in what he teaches.
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  #18  
Old 04-23-2015, 10:57 AM
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andrewrodney andrewrodney is offline
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Re: Is Lab color (L*a*b*) still relevant?

AFAIK, Dan retired.

But let's revisit this a bit. Let's ask bigger questions than is Lab relevant and what tasks retouchers specifically should have to worry about. The advise by some over the years is "Sharpen in Lab" because otherwise one affects color. Let's forget the fact that one can do this in RGB and produce the same results of avoiding issues with color and instead look at sharpening.

In the old days, sharpening was applied at the scan stage at a specific resolution and for a specific output. So let's forget that this wasn't capture sharpening and the task was done with output in mind. Did retouchers feel they needed to further sharpen the image, using Lab or otherwise? Let's look at images that come from raw data, as today, that's far more common than film or film scans. Are retouchers getting rendered images from raw with no sharpening? If so, would it be better if sharpening were applied at the raw processing stage and if so, would that allow retouchers to do the work they are best trained to do; retouch?

Let's look at the majority of awful images in Dan's book. There is no question he, as prepress operator received such awful images to fix. Given that professional photographer that pays for professional retouching should never produce such awful work, where then is the need by and large, for Dan's techniques? I don't know the answer to what kinds and qualities of work retouchers here receive, I know the kind of quality of imagery a trained photographer should provide. None falls into the camp we see in Dan's book.

So, should retouchers get the highest quality data and imagery possible before they do their creative work and can they? Should they have to concern themselves with sharpening captures and fixing exposure and color casts? The answer is of course yes, sometimes, but as a rule? I'd hope not. Can and should a retoucher start with raw data or is that the domain of the image creator? Can they work together in this respect? If so, I submit, the techniques we see in Dan's book using Lab are virtually unnecessary. This isn't to say a retoucher will never get a poor quality rendered or scanned image that needs fixing. Just as I'm sure, retouchers are given tiny files that need to be printed large. But that should be the exception, not the rule.

What I see a lot in terms of people discussing retouching is techniques and processes like how to sharpen or fix a color cast or even convert to B&W. Useful, somewhat easy to describe. Teaching someone how to make a celebrity look 10lbs lighter and 10 years younger without it looking like an obvious Photoshop job is much harder to do and describe. So I think the techniques we read about dealing with Lab are less salient today then ever before.

OK, off to view Cox's video's to get his take on Lab.
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  #19  
Old 04-23-2015, 01:41 PM
Shoku Shoku is offline
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Re: Is Lab color (L*a*b*) still relevant?

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Originally Posted by Doug Nelson View Post

Was it a workaround that has since been surpassed by clearer and more direct methods? Or just more of a headache than it's worth? Or do the Lab fans just hang out elsewhere?
Getting back to the original question: LAB is a tool retouchers can use. Like a mechanic, a good retoucher should have a complete tool set to tackle anything that comes along. Sometimes LAB is not the answer. Sometimes it is.

We receive files from hundreds of sources, some professional, some not. RAW submissions are rare, and often come without the XMP file that saves the Photographers corrections. When we get a RAW file that shifts our focus to Camera RAW and the desired results can be amazingly quick and simple to achieve. But again, RAW file submissions for us are few.

We need to adjust our tool set for every order submitted, as I'm sure is the case for most retouchers. Whether it's LAB, RGB, or CMYK, we chose what works best for the image we're currently working on.

As a side note, we output our scans to LAB, which makes the process simpler and avoids some of the color shift issues we had before making that change.
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  #20  
Old 04-23-2015, 01:49 PM
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andrewrodney andrewrodney is offline
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Re: Is Lab color (L*a*b*) still relevant?

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Originally Posted by Shoku View Post
RAW submissions are rare, and often come without the XMP file that saves the Photographers corrections. When we get a RAW file that shifts our focus to Camera RAW and the desired results can be amazingly quick and simple to achieve. But again, RAW file submissions for us are few.
I wonder why and if this could be changed if even a little. I know many photographers have issues providing a raw file, they feel it's like giving away a negative. I wonder if some of the problematic images were raw to begin with and if upstream, this could be better rendered.

But much of the problem isn't technical, it's political. For years and years, people have been handed CMYK data that isn't close to being optimized for output and those folks have to handle data that simply isn't appropriate for best results.
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