Lightroom and Camera Raw Color Range Mask Edge Artifacts

  • 1
  • Problem
  • Updated 4 months ago
  • (Edited)
The Local
Adjustment Color Range Mask appears to be calculated using the image data before Chromatic Aberration (CA) and Defringe are applied. This causes the Color Range Mask adjustments to be applied to image edges that have chromatic aberration. It creates a visible edge outline of size and color dependent on the type and severity of the lens chromatic aberrations. I tested this using a Canon EF 16-35mm F/4L IS lens that has very low CA and the Canon EF-S 18-35mmF/3.5-5.6 IS II, which has much higher CA. To confirm this analysis I created Export TIFF copies of the raw image file with Lens Corrections> Profile> ‘Remove Chromatic Aberration’ unchecked and checked. The TIFF with ‘Remove Chromatic Aberration’ unchecked appears identical to the raw file and exhibits the same edge artifacts. The TIFF with‘Remove Chromatic Aberration’ checked displays almost NO artifacts.

EDIT: The Adjustment Brush ‘Auto Mask’ control exhibits the same behavior as the ‘ColorRange Mask’ control when 'Remove Chromatic Aberrations' is unchecked.


SUGGESTEDSOLUTION


Calculate the ‘Color Range’ mask and ‘Auto Mask’ using the image data with both ‘Remove Chromatic Aberration’ and Defringe controls applied. Since this may impact performance of the Local Adjustment tools a workaround should be implemented.Allow applying the Adjustment Brush and Radial Filter Local controls just as they are now to minimize impact to performance. Add a ‘Refine Edge’ button to the ‘Range Mask’ and ‘Auto Mask controls that can be used after the local controls are applied if the image exhibits the edge artifacts. The mask can then be recalculated with Chromatic Aberration removal and Defringe applied to the image data. This “refinement” will take additional time, but won’t impact performance during initially application of the Adjustment Brush and Radial Filter local controls.


Canon EF 16-35mm F/4L IS lens
3:1 Zoom View


Canon EF-S 18-35mm F/3.5-5.6 IS II
3:1 Zoom View
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Todd Shaner, Champion

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Posted 4 months ago

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Peter Moloney

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Well explained Todd!
I have experienced this as my last step before "processing" the images is to apply a little sharpening and remove CA and defringe (Mostly 24mm TSE lens) in the form of my own preset.

To apply the remove CA filter before masking makes the tool unworkably slow, (5DsR files)
Really interesting observation!
Peter
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Todd Shaner, Champion

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Peter, 'Remove Chromatic Aberration' and 'Defringe' do not appear to affect the Adjustment Brush performance on my Windows 7 system. What does affect it are the Detail panel's Luminance and Color Noise Reduction. Try it for yourself.

Set the Detail panel's Luminance and Color Noise Reduction Amount sliders both to 0, 'Remove Chromatic Aberration' checked, and Defringe with your settings. Try the Adjustment brush. Now set the Luminance or Color Noise Reduction Amount slider to a value of 1 or higher. Now the Adjustment brush should be a lot slower and laggy.

What's interesting is that with 'Remove Chromatic Aberration' and 'Defringe' checked the Adjustment Brush Loupe preview shows them as applied. However, it's clear form my above tests that the Color Range' mask is calculated with them NOT applied. That's the issue Adobe needs to correct and they should be able to do that without affecting performance using my above suggestions.
(Edited)
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Peter Moloney

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Great News! Works on OS X 10.12.6 too. This I didn't know!
I have now made separate presets - Remove CA and defringe which I'll now do before local adjustments, and sharpen and noise reduction which I'll do at the end! Thank You!
Peter
(Edited)
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Todd Shaner, Champion

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Good to hear that it works the same on OS X! Just to clarify for others landing here you modified your Develop preset to apply Sharpening and Noise Reduction after making Local edits to speed up the Adjustment Brush. You've also created a separate Develop preset to apply 'Chromatic Aberration' and lens specific 'Defringe' controls on Import before any editing.

Let me add that you can apply Sharpening on Import as well since it does not appear to affect the performance of the Local Controls. This is useful to allow apply additional Sharpening to selected areas of the image.

I also would like to clarify that the Adjustment Brush ‘Auto Mask’ control does NOT create any edge artifacts as long as 'Remove Chromatic Aberrations' is checked. I've edited my previous replies to reflect this observation. Hopefully Adobe can correct the Color Range mask so that it behaves the same as 'Auto Mask'. Enjoy!