Curves layer in Luminosity?

[transoptic]

Would it be advantageous to make your curves layer in Luminosity mode to avoid color shifts? Does anyone do this? I get a feel that I retain saturation better this way.

[Flashtones]

It's very advantageous to do so - if you don't want color shifts - but not if you do. For instance, steepening the curve will add contrast and saturation, which often times one does wish to increase or decrease simultaneously. For instance if you have a dull flat image, a steepened curve will increase tonal contrast and saturation yielding more "pop" in one simple move.

Anyway, curves can do so much you wouldn't want to limit them as a rule. But sometimes it is helpful to isolate your tone, hue and saturation adjustments.

[jam1212]

I think it was Chris T. who first made the point that even in luminosity mode, color shifts still occur. If I remember correctly, it actually adds a bit of cyan to the image when in luminosity mode. It's one of the things he's hoping Adobe will fix in future versions of PS.

But, regardless of the minor shift that still remains, the overall effect is much less jarring than a normal curves layer, so in certain situations it is definitely advantageous.

[namphoto]

Curves in normal can add a natural saturation that Luminosity does not. As subjects have more light, often they are more saturated.

[Quantum3Studio]

It's not the same editing in L*a*b than in RGB and setting curves to Luminosity.

[AngeloLorenzo]

I use it liberally. Because it doesn't add saturation, it tends to make colors kind of bleak and desaturated when large adjustments are made.

Luminosity curve layers are what I use masked off for light dodging and burning.

Another fun one is setting the layer mode to color and adjusting the individual color curves. Corrects color without introducing overall changes in contrast.