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You are here: Home / Color Science / Why no love for Luv?

Why no love for Luv?

May 13, 2022 JimK 2 Comments

I’ve always liked looking at colors  and color relationship in both CIEL*a*b* and CIEL*u*v*. Neither is perfectly perceptually uniform, and on average, they’re both about the same distance away from that. A couple to times I’ve looked at averaging the two, but nobody else does that, so I haven’t published any of those graphs.

But nobody here talks about Luv. Why is that?

Lab and Luv come from different industries. The ancestors of Lab were used in the printing industry and in assessing hard copies. The forbearers of Luv were in industries that used self-luminous displays. They were both codified at the same time, about 13 years before I got involved in color science professionally. I’ve been out of the biz for going on 30 years now, so I’m unaware of how the color space politics has progressed.

Was Photoshop’s late-80s decision to support Lab but not Luv important? Maybe so. I’ll be many photographers got their introduction to Lab through Ps.

The ICC’s blessing of Lab as the reference space may have also played a role.

And then there’s the fact that Lab has been enhanced over the years since 1976, while I don’t think that Luv has received any improvements.

Is this a QWERTY thing? At the beginning of Ps, the program was mostly aimed at post production for printing. Now, it seems like most people are thinking more about self-luminous media. But maybe the die was cast?

Luv has some nice features. It has a saturation metric that makes a lot of sense. The derivation from XYZ, while having its share of heuristic decisions, seems less so that Lab. The ability to include the spectral horseshoe on chromaticity plots is a plus.

But I don’t see people using it. The reason that working photographers don’t use it has to hinge on the fact that it’s not supported in the reference tool. But why isn’t it?

Color Science

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Comments

  1. JaapD says

    January 12, 2023 at 11:00 am

    Hi Jim,
    Thanks for this post. I really like Lab. I use(d) it for my sharpening action where I only apply sharpening in the luminance channel, leaving the color channels unaffected. From experience I can say that with this I’m able to apply a more natural sharpening before the end result gets over the top.

    (background info: I copied this ‘trick’ from the old 3 CCD / 3 Plumbicon analog image processing pipeline with the broadcast cameras where sharpening was also applied only in the luminance channel, leaving the color difference channels unaffected)

    Cheers,
    Jaap.

    Reply
    • JimK says

      January 12, 2023 at 12:00 pm

      Yes. I used to do that in the early 90s. I think that would work equally well in Luv.

      Reply

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