my 2min-version of the 2nd image:

https://jo.dreggn.org/neon.jpg

the neon lights are indeed something that doesn't seem to be covered
well at all by the reference it8 chart. we probably need to somehow
extend the darktable-lut module to read not only well defined colour
patches but also random images (as the basecurve tool does). but even
then it would just be cloning the jpg engine.. which is sub-optimal
imo. i get much improved results when switching on gamut clipping in
the input colour profile module (see xmp embedded in the jpg). i
suspect the camera manufacturers do similar things on chip.

-jo


On Tue, Apr 26, 2016 at 10:21 PM, J. Liles <malnour...@gmail.com> wrote:
> Here are some of my problem images.
>
> http://www.nevermindhim.com/fuji-xtrans-samples
>
> Also included on the page is my style for denoising.
>
>
> On Tue, Apr 26, 2016 at 11:04 AM, J. Liles <malnour...@gmail.com> wrote:
>>
>> Group,
>>
>> I've recently acquired a camera with an X-Trans sensor, and have had
>> little trouble generating images that contain areas prone to demosaicing
>> artifacts.
>>
>> Is anyone interested in these? If so, is there a certain place I should
>> host/send them? I have camera generated JPG for comparison along with the
>> RAF files.
>>
>> In playing around I've discovered a few things:
>>
>> 1) Color smoothing is mandatory, as fine lines and especially specular
>> highlights will always generate nasty color artifacts when using the baisc
>> demosaicing. Seems like a smarter highlight recovery algorithm could help
>> identify many of these problem spots.
>>
>> 2) None of the 'denoise' modules have sufficient parameter ranges to deal
>> well with the X-Trans files.
>>
>> 3) When sufficient denoising is performed to remove maze and color
>> artifacts, the difference between VNG and Markesteijn demosaicing is
>> indiscernible.
>>
>> I have a style preset which can produce images that match the camera JPGs
>> as far as noise/detail goes (utilizing the equalizer module) at ISO 3200.
>>
>> Color is another matter, but I've ordered one of the Wolf Faust IT8 charts
>> to try and make an ICC profile.
>>
>> (I tried making one using the imaging-resource.com multi target studio
>> shots, and while the results were OK, they weren't great).
>>
>> P.S. Is there any plan to support Fuji's RawExposureBias exif tag? It is
>> necessary to display high ISO RAF images at the correct brightnesss.
>
>
>
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