Reading the dithering method man pages. That's really what I wanted. Cant wait to try it.
And what a coincidence: the Hot Pixels method is explained right after that. Thanks again, André Felipe 2015-11-12 14:42 GMT-02:00 André Felipe Carvalho <afelipe.carva...@gmail.com >: > Great, Jo! > > I've never understood the purpose of this method. Maybe now the time has > come for me to understand it. > > (out of this topic, I've never used the HotPixels module before a couple > of weeks, when some photos shot at night, toward a source of light, showed > 2 or 3 pixels, one red, another blue, in the middle of the black area. > First I thought about spot removal, but then... I turned Mark Hot Pixels on > and voilá, those pixels vanished! Great! [if anyone wants to explain > what's that, you're welcome]) > > I'll try the dithering when I get home, tonight, and post the results > later. > > Thank you all. > > André > > > 2015-11-12 12:18 GMT-02:00 johannes hanika <hana...@gmail.com>: > >> right, this kind of artifact results from low bit depth even for >> perfect images without noise reduction. ulrich wrote the dithering >> module to counteract that: >> >> http://www.darktable.org/usermanual/ch03s04s04.html.php#dithering >> >> might be helpful in your case, too. >> cheers, >> jo >> >> On Thu, Nov 12, 2015 at 3:08 PM, André Felipe Carvalho >> <afelipe.carva...@gmail.com> wrote: >> > This photo was saved in jpeg 100%, raw denoising of 0.004. I managed to >> get >> > rid of the majority of the bands, but you can see some lines >> above/around >> > the sun. >> > https://www.flickr.com/photos/andrefelipecarvalho/22536463868/ >> > >> > >> > >> > 2015-11-11 22:34 GMT-02:00 André Felipe Carvalho >> > <afelipe.carva...@gmail.com>: >> >> >> >> Hello Johannes, >> >> >> >> I was using Jpeg 97% >> >> >> >> I use, normally, only the raw denoising, starting with 0.002 points, >> going >> >> to 0.006 if needed and the image colors permit. >> >> >> >> Experimenting with 0.004 raw denoising I can see some band even with >> the >> >> PNG 100% export. But I admit it's better then at 97% jpeg. >> >> The bands, now, are narrower than before. Less visible at the orange >> sky >> >> parts and more apparent at the dark, silhouetted parts. >> >> >> >> Pulling the Color Balance first factor (Levantar, in portuguese) a >> little >> >> bit to the left may help to disguise the bands. >> >> >> >> Thanks again, >> >> André >> >> >> >> >> >> 2015-11-11 14:24 GMT-02:00 johannes hanika <hana...@gmail.com>: >> >>> >> >>> On Wed, Nov 11, 2015 at 11:05 PM, Tobias Ellinghaus <h...@gmx.de> >> wrote: >> >>> > Am Dienstag, 10. November 2015, 19:15:10 schrieb André Felipe >> Carvalho: >> >>> >> I've been experiencing this behavior specially in sunset photos. >> >>> >> >> >>> >> After applying the modules that I want, among them the sharpness >> >>> >> module, if >> >>> >> I want to get rid of the raw noise, the exported jpeg shows bands >> on >> >>> >> the >> >>> >> degrades parts of the image (sky, for instance, or dark areas). >> >>> >> The exported image without Raw Noise Reduction is about 6.8MB, >> while >> >>> >> the >> >>> >> one with noise reduction goes down to 2.8MB. Why's that? >> >>> >> >>> that's normal, noise has high entropy and doesn't compress as well as >> >>> the low noise one. >> >>> >> >>> did you only do raw denoising? or any non local means, too? any >> >>> wavelet based method shouldn't lead to as much banding as nlmeans >> >>> (because the latter uses a piecewise constant prior). >> >>> >> >>> -jo >> >>> >> >>> > >> >>> > - What is your "quality" setting in the export module? >> >>> > - Could you try exporting to PNG and see if that has the same >> problems? >> >>> > >> >>> >> The IQ is bad (because of those bands) and I have to turn noise >> >>> >> reduction >> >>> >> off. >> >>> >> >> >>> >> I can provide some samples, or the raw file and the .xml >> associated. >> >>> > >> >>> > Tobias >> >>> > >> >>> > >> ------------------------------------------------------------------------------ >> >>> > >> >>> > _______________________________________________ >> >>> > Darktable-users mailing list >> >>> > Darktable-users@lists.sourceforge.net >> >>> > https://lists.sourceforge.net/lists/listinfo/darktable-users >> >>> > >> >>> >> >>> >> >>> >> ------------------------------------------------------------------------------ >> >>> _______________________________________________ >> >>> Darktable-users mailing list >> >>> Darktable-users@lists.sourceforge.net >> >>> https://lists.sourceforge.net/lists/listinfo/darktable-users >> >> >> >> >> >> >> >> >> >> -- >> >> André Felipe >> >> ============================================ >> >> New beginnings are often disguised as painful endings. >> >> >> >> >> -------------------------------------------------------------------------------- >> >> Lao Tzu >> >> ============================================ >> > >> > >> > >> > >> > -- >> > André Felipe >> > ============================================ >> > New beginnings are often disguised as painful endings. >> > >> > >> -------------------------------------------------------------------------------- >> > Lao Tzu >> > ============================================ >> > >> > >> ------------------------------------------------------------------------------ >> > >> > _______________________________________________ >> > Darktable-users mailing list >> > Darktable-users@lists.sourceforge.net >> > https://lists.sourceforge.net/lists/listinfo/darktable-users >> > >> > > > > -- > André Felipe > ============================================ > New beginnings are often disguised as painful endings. > > -------------------------------------------------------------------------------- > Lao > Tzu > ============================================ > -- André Felipe ============================================ New beginnings are often disguised as painful endings. -------------------------------------------------------------------------------- Lao Tzu ============================================
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