Haze removal dark halo

In darkroom, when I turn on haze removal (default values), a dark halo is clearly shown on the back of the dog.
When I export the image, however, I don’t see it.
Is it normal?

In darkroom, haze removal off:

In darkroom, haze removal on:

Exported image, haze removal on:

As many local filters (relying on blur to… blur or sharpen : gaussian, bilateral, guided filter, wavelets, etc.), haze removal is slightly sensitive to zoom level (through its internal guided filter) and will not appear the same depending on pixel scaling. Also the haze removing is sensitive to image exposure level, sometimes it is better to move the module before or after exposure in the pipe.

Anyway, this is not a valid use case for haze removal since this picture has no hazing in the first place and the algorithm is grounded into light diffusion through droplets. You might better use contrast equalizer for that purpose.

You mean the lens zoom, right? Because I didn’t cropped the image. Just to make sure I get the right direction (not understanding, because your theory goes beyond my capacity :sunglasses:)

Agreed.

No, not the lens zoom, the pixel scaling. The preview you see in darkroom is scaled from the original image resolution to the screen resolution. Every effect you see in there is computed at screen resolution. Then, during export, resolution is rescaled from image to export size, either at the beginning or at the end of the pixelpipe (if using “high quality export”). That’s why you get discrepancies.

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