Lightroom: Adjustment brush with Auto Mask ON leaves ugly artifacts in noisy images

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  • Updated 2 years ago
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As I understand it, LR applies adjustments in a pre-determined order independent of the order in which the user applies them.   According to this discussion LR applies local adjustments before global ones.  If this is true, then if I reduce noise (global) and then paint +1.0 exposure (local), LR paints the exposure first and then reduces noise.  But painting exposure amplifies noise, making it harder to reduce, leaving ugly artifacts.  For some reason, this happens only when Auto Mask is ON.

Perhaps the analysis is wrong, but not the conclusion:  Using the adjustment brush with Auto Mask ON leaves ugly artifacts in noisy images.  See also this post from 4 years ago.
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John Isner

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Posted 2 years ago

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Todd Shaner, Champion

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As explained at the Lightroom forum discussion link the Local controls are applied before the Global controls. This means that when using the Adjustment Brush 'Auto Mask' function with high ISO noisy images the mask algorithm confuses noise as image data and does not apply the mask in those spots. This creates small holes in the mask where noise is present creating a "speckled" look to the area. One solution is to first apply Global adjustments to the image file including Noise Reduction, Export to a ProPhoto RGB 16bit TIFF file, and then apply the Local controls to the rendered TIFF file. More at the below link: