Adobe Camera Raw - ACR3 & ACR4

[Dinarius]

In ACR, do changes to the sliders in the Adjust tab (Exposure, Shadows, Brightness, Contrast etc...) affect only luminosity, or do they also affect colour? i.e the underlying Hue/Saturation?

In other words, are adjustments similar to those in PS with Blending Option set to Luminosity?

If some sliders do and some don't, which ones are they?

Many thanks.

D.

[digitaldog]

In ACR, do changes to the sliders in the Adjust tab (Exposure, Shadows, Brightness, Contrast etc...) affect only luminosity, or do they also affect colour? i.e the underlying Hue/Saturation?

In other words, are adjustments similar to those in PS with Blending Option set to Luminosity?

If some sliders do and some don't, which ones are they?

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My understanding is yes, they only affect luminosity. I don't want to say that's true for 100% of the controls you mention because I'm not 100% certain but I'm pretty sure that is the case (Jeff?).

[digitaldog]

I'm moderating a panel today with Mark Hamburg and Thomas Knoll at Photoshop World (Soup to Nuts) and if time permits, I'll ask your exact question to the panel (its a good one). Let you know tomorrow.

[Schewe]

Contrast does effect color...increase contrast and the sat jumps. That's been point out to Thomas. He pretty much shruggs...stuff happens ya know?

So, no, it's not entirely a luminosity based tone adjustment...everything is interconnected to a degree. Note also that color can effect tone-white balance has an impact on brightness.

[Dinarius]

Contrast does effect color...increase contrast and the sat jumps. That's been point out to Thomas.
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Are you implying by your answer that the other sliders don't affect colour?

Thanks.

D.

[Dinarius]

One further observation.....

If you make adjustments in the H/S tab and then return to the Adjust tab to make tonal adjustments, those adjustments that you have made in the H/S tab don't change.

Does this indicate that the Adjust tab is colour independent?

Also, in his discussion about calibration using a Gretag Macbeth CC ('Camera Raw with Adobe Photoshop CS2' p.100) Bruce Fraser wrote, "But, don't forget to zero out the Adjust and Curve tabs to your desired default rather than the very low contrast settings required by the exercise!" This would seem to me to imply, that the zeroing-out does not affect the colour correction of the exercise.

D.