Have you taken a look at the jpeg quality export options? Is it at 100%
quality?
2013/2/12 Ken March <[email protected]>
> Greetings!
>
> Currently I'm editing 28 very noisy sports photos. They were all shot
> outdoors under a heavy cloud cover, late in the afternoon near dusk, at
> 1600 ISO and a slow lens (F5.6 to F5.0) on a 15 mega-pixel camera, (Canon
> 500D).
>
> After I edited, and exported 4 of these photos to jpeg, I noticed
> differences between the noise in the jpeg files versus what is seen in
> darkroom.
>
> I'm new to darktable, so I'm wondering if this might be user error!
>
> For one of these files in question, I have a screen-shot of what darkroom
> displays, as well as the jpeg, xmp file, and originating cr2 file available
> here,
> https://www.dropbox.com/s/2wb2p3zzqokpnqg/denoise-differences.zip(~22MB).
> (First time sharing via dropbox, so let me know if I've screwed it
> up.)
>
> For reference, the denoise tools that I've implemented are:
> 1. raw denoise – threshold 0.01, blend mode unbounded, opacity 100%
> 2. demosaic – amaze, edge threshold 0.003, color smoothing 2 times, match
> greens full and local avg
> 3. denoise (non-local means) – patch size 3, strength 100%, luma 50%,
> chroma 100%, blend mode unbounded
> 4. sharpen – radius 2, amount 0.5, threshold 0.5, blend mode off
>
> The differences are subtle, but exist. In particular there are two things
> I've noticed:
>
> First,the noise seen in the pavement in the foreground and of the bumper
> sides around the lower portion of the karts is smoother in darkroom (as
> seen in the example screen-shot) than as seen in the jpeg. The zoom level
> is 1.5:1, btw.
>
> The second discrepancy is that in the jpeg there a couple of light dots on
> the leading kart's bumper in the area in front of his rear wheel, which are
> not seen in the darktable screen-shot.
>
> Why is there a discrepancy between what is seen in darktable versus the
> exported jpeg?
>
> (I hope the answer is user error! :-) )
>
> It will improve my work flow to understand this discrepancy.
>
> Kind regards,
> Ken
>
>
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--
Un saludo,
Salvador Laiz
[image: fulgacian - View my most interesting photos on
Flickriver]<http://www.flickriver.com/photos/fulgacian/popular-interesting/>
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