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

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Old 04-22-2015, 05:36 AM
Doug Nelson's Avatar
Doug Nelson Doug Nelson is offline
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Is Lab color (L*a*b*) still relevant?

Aside from the occasional "Photoshop secret" tip I rarely see Lab mentioned anymore. Obviously the option is still there, and it works the way it always has, but it used to be touted as the ultimate guru technique.

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?
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Old 04-22-2015, 02:34 PM
klev klev is offline
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Re: Is Lab color (L*a*b*) still relevant?

In my opinion these things tend to gain popularity due to edge cases where other algorithms are unstable unstable under certain conditions or may align to produce undesirable results. Converting between color spaces isn't ideal whenever it's avoidable, as you always lose some precision, and it's problematic to preserve layers.

Do note that edge cases still exist with color correction algorithms. They've just improved quite a bit. For example if you look at brightness/contrast now compared to say photoshop 7, you'll see that the current one applies a scale factor to its channel values. I'm not sure what the old one did, but this certainly results in less color shift. Companies as big as Adobe tend to avoid sweeping changes wherever possible, because it can hurt the ability to access old images. They dealt with that by allowing you to embed a flattened version.
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Old 04-22-2015, 02:50 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
Aside from the occasional "Photoshop secret" tip I rarely see Lab mentioned anymore. Obviously the option is still there, and it works the way it always has, but it used to be touted as the ultimate guru technique.

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?
Photoshop LAB is still there and it still works. A valuable color space that can handle many correction problems quickly and easily. When you don't need it you probably won't miss it, but if you do need it, you'll be glad to have it, if you know how to use it, and know when to use it.
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Old 04-22-2015, 02:54 PM
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Re: Is Lab color (L*a*b*) still relevant?

I think it was Chris Cox in one of my shows, but I'm not going to wade through 6 hours of video to find out, but it was definitely an Adobe engineer that told me that working in Lab was unnecessary effort because Photoshop did everything in Lab behind the scenes anyway.
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Old 04-22-2015, 03:00 PM
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Re: Is Lab color (L*a*b*) still relevant?

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Aside from the occasional "Photoshop secret" tip I rarely see Lab mentioned anymore.
Thank goodness. And if Chris Cox had a show, I'd love to see it. I know Chris dating back to before he was a Photoshop engineer and just a kid. Anyone here recall "Chris's Filters"? The work impressed Thomas Knoll and Adobe hired him up just out of school.
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Old 04-22-2015, 03:07 PM
klev klev is offline
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Re: Is Lab color (L*a*b*) still relevant?

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but it was definitely an Adobe engineer that told me that working in Lab was unnecessary effort because Photoshop did everything in Lab behind the scenes anyway.
Photoshop probably uses LAB as a profile connection space in their CMM. If adjustments are computed relative to the CMM rather than the RGB space, he would effectively be telling the truth. From a user perspective the behaviors don't really match though.
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Old 04-22-2015, 03:11 PM
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Re: Is Lab color (L*a*b*) still relevant?

Yes, it does use Lab as within it's CMM. But not for much else. There's an old urban legend that PS does 'everything', all operations in Lab, not so. Actual conversions to and from Lab (as you'd do in Mode Change) are too slow and unnecessary. What Photoshop does is it builds a conversion table and to do so, it uses LAB to find the equivalents from source to destination in cases where it needs to translate such color spaces, using 20-bit precision so you get less quantization errors than you would actually converting the pixels to LAB.
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Old 04-22-2015, 03:12 PM
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Re: Is Lab color (L*a*b*) still relevant?

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Originally Posted by andrewrodney View Post
Thank goodness. And if Chris Cox had a show, I'd love to see it. I know Chris dating back to before he was a Photoshop engineer and just a kid. Anyone here recall "Chris's Filters"? The work impressed Thomas Knoll and Adobe hired him up just out of school.
He actually did 2 shows:
http://www.retouchpro.com/index.php?page=ccrentals
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Old 04-22-2015, 03:13 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
I think it was Chris Cox in one of my shows, but I'm not going to wade through 6 hours of video to find out, but it was definitely an Adobe engineer that told me that working in Lab was unnecessary effort because Photoshop did everything in Lab behind the scenes anyway.
Using LAB as a correction space gives the user access to three color channels not available in RGB or CMYK. Because of this some adjustments are easier when done in LAB. It is not unnecessary effort when you can save time and accomplish more, with better results.

Last edited by Shoku; 04-22-2015 at 06:39 PM.
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Old 04-22-2015, 07:17 PM
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Re: Is Lab color (L*a*b*) still relevant?

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.
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