LIGHTROOM: Noise reduction cause halo artifacts on 32-bit HDR images

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  • Updated 6 years ago
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I face the same issue. Global noise reduction with 32bit TIFF files is almost not usable. Whenever bright parts appear in the image and the Luminance slider is pushed above zero (1 to 10 is enough) , "halo artifacts" build up around these bright parts. They can reach far into the rest of the image. The severity and significance of this problem is not really shown in the example of the thread opener.

I think the most important fact to realize is that with 32bit TIFFs either the noise reduction luminance is so low (e.g. 1) that you cannot achieve any visible effect on noisy surfaces or you push it up to 10 or so, where things start to improve in most parts of the image, but these ugly artifacts also appear around bright parts. That's why the thread opener and me come to the conclusion that you cannot use this feature with (a lot of) 32bit TIFFs.

Consider this 32bit TIFF in Lightroom 4.2 (no noise reduction enabled):

Now, I've increased the noise reduction luminance to 7:

This clearly is a problem.

It looks like in case of these edges the noise reduction algorithm sees an extreme local discontinuity in brightness in which case it creates artifacts. I understand that this discontinuity can be much larger in 32bit images than anywhere else. However, in the example pictures I've reduced the jump in brightness a lot via local exposure adjustments and global shiftings of highlights/whites. Maybe the noise reduction algorithm should take these adjustments into account.

My workaround is to finish editing in 32bit, export to 16bit TIFF and apply global noise reduction as the very last step within this 16bit image. There, no artifacts show up.

Note: This topic was created from a reply on the Lightroom: Extreme blurring using noise reduction and 32-bit TIFF's topic.
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Peter Müller

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Posted 6 years ago

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Dorin Nicolaescu-Musteață, Champion

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