Edge and Surface Masks

[ravel03]

Hi,

In the Details panel, I'm wondering how ACR 5.5 applies Noise Reduction (both, luminance and color) on my images. Does it do it globally (no masking)? Or does it calculate a surface mask (that could be based on the inverse of the edge mask that one can setup using the Masking slider) and apply NR to surfaces only?

One more question. Is ACR's process pipeline taking care of NR before or after Sharpening? I'm asking because, from UI perspective, the noise sliders are after the sharpening ones (leading to confusion, at least for me).

Thanks.

-stéphane

[Schewe]

In the Details panel, I'm wondering how ACR 5.5 applies Noise Reduction (both, luminance and color) on my images. Does it do it globally (no masking)? Or does it calculate a surface mask (that could be based on the inverse of the edge mask that one can setup using the Masking slider) and apply NR to surfaces only?

The noise is applied with an edge-sensitive algorithm yes, but no, it's not the same as the sharpening mask...the noise reduction works on a far smaller scale to try to determine what is real image detail and what is simply noise. It then steps on (blurs) just the noise while trying to preserve real image detail.

Is ACR's process pipeline taking care of NR before or after Sharpening? I'm asking because, from UI perspective, the noise sliders are after the sharpening ones (leading to confusion, at least for me).

You don't need to worry about the order in which Camera Raw works...it ALWAYS works in its own optimal processing order regardless of the order in which the user makes adjustments. ACR is a "parametric" editor and as such it's always ONLY editing the parameters applied to the image when it's actually processed. And the pipeline for the processing is always the same optimally ordered one designed by the engineers (and it's a lot more complicated than can be explained here).

[ravel03]

All questions answered. Thanks for that.