0.92: Downscaling with gamma correction posterizes dark areas

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Daniel710
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0.92: Downscaling with gamma correction posterizes dark areas

Post by Daniel710 »

XnView: MP 0.92 - 64 bit
OS: Linux

Downscaling an image with gamma correction posterizes dark areas. See the attached image (50% size of the original).

To reproduce, downscale an image with "Use gamma correction" enabled.
PIA11667.jpg
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xnview
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by xnview »

The original have posterized area
Pierre.
Daniel710
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by Daniel710 »

The posterized image you see in my post is the downscaled version of the original. I don't see any artifacts on the original image:
Image
Daniel710
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by Daniel710 »

Still reproducible in XnView: MP 1.3 (and also in XnResize, btw).
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xnview
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by xnview »

i can't reproduce with your sample image, which output size do you use? could you post the output?
Pierre.
Daniel710
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by Daniel710 »

Try downscale to e.g. 1806x961 pixels. You can see the output image in the first post: download/file.php?id=5149&mode=view
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xnview
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by xnview »

where do you see "posterized area"?
Pierre.
Daniel710
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by Daniel710 »

On the Saturn rings. I attached an image with side-by-side comparison.
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Strip 2.jpg
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xnview
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Re: 0.92: Downscaling with gamma correction posterizes dark areas

Post by xnview »

yes a known issue on dark color
Pierre.
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