2017-03-04 8:00 GMT+01:00 <[email protected]>: > Hello, > > Thank you for your answers. > > On 2017-03-03 15:58, Chris Siebenmann wrote: > >> I recently purchased a Canon EOS 80D, I am a Debian (8.7) user. All this >>> is quite new to me so it might be a newbie question rather than a >>> problem with Darktable. Sorry beforehand if that is the case. >>> >>> TL;DR: http://imgur.com/a/eEipd >>> >>> When importing photos (CR2) into Darktable (2.0.7), >>> colors/contrast/brightness... aren't the same as in the "Gnome Document >>> Viewer" preview (and on the screen of my 80D). >>> >> >> What I suspect is happening here is that the version of the image that >> the Gnome Document Viewer preview and the 80D are showing you comes from >> a 'preview' JPEG that is embedded into the RAW file (most RAW files have >> several preview JPEGs in them at various sizes). This preview JPEG has >> had all of the camera-specific magic processing applied to it, including >> any in-camera styles you either set yourself or that Canon applies by >> default. >> >> The darktable picture seems to be from the darkroom, where darktable >> is processing the RAW itself from scratch. This from-scratch processing >> almost never exactly duplicates the camera's own processing (partly >> because camera makers never tell anyone what the in-camera stuff is >> actually doing), and is sometimes not at all similar to it depending on >> what settings the camera and darktable have. Generally the further from >> 'basic neutral' you have the camera on, the more divergence there is >> going to be. >> >> (Note that most cameras don't come set to 'basic neutral' out of the >> box; usually their default picture setting is more cranked up than that, >> because it looks nicer on the back of the screen and when people just use >> the JPEG defaults.) >> >> This is an issue in any RAW processor (apart from the ones from the >> camera companies themselves), because none of them know exactly what >> the in-camera processing is doing. Some RAW processors devote more >> engineering and development effort to closely matching the straight >> out-of-camera processing than others do, and so will come closer to the >> look of those JPEGs by default. My impression is that darktable chooses >> to focus development efforts elsewhere, so it winds up not necessarily >> very close for many cameras and many camera styles. >> >> (There are ways to get it closer in some areas if you want to do >> some hand work. There are darktable tools that take some RAWs and >> some corresponding JPEGs and work out much of the intensity/contrast >> mapping between them to create a custom 'base curve' for the camera and >> style. However cameras also often add things like colour shifts and >> various sorts of sharpening and so on, and those are generally not going >> to be duplicated through the base curve's mapping of intensities.) >> > > That is insightful, thank you. Using the "base curve" tool, and selecting > the "eos like profile really helps. > > Playing around withe the various modules in the darkroom, I managed to get > close to the "preview jpg" render (I find it close to what I shot - through > the viewfinder, in manual mode - particularly, regarding colors). > > 1: CR2 as seen by the Document viewer ; > 2: Darktable default ; > 3: Darktable edited (base curve, contrast, shadows, demosaic, sharpen). > > https://imgur.com/a/0M3ez > > I am still having a hard time reproducing the same (~ red) color for the > trackpoint (look at #1 and #3 side by side, #1 is the real color). Any clue > on what module to use to fix that ? > > On 2017-03-03 16:29, Roman Lebedev wrote: > >> Also see >> https://www.darktable.org/2016/05/colour-manipulation-with- >> the-colour-checker-lut-module/ >> > > Thank you. > > I got to say that I laughed out loud reading this article. I hold a > masters degree in engineering and reading through it felt like reading > Klingon. > > There are so many undefined acronyms (ICC and LUT aren't defined for > instance (I actually had to wait until the 6th iteration of LUT to get a > confirmation that the author was actually talking about lookup tables)) or, > when it comes to formulas, undefined parameters (like "CIE 76 ΔE")). > > This being said, and after googling every undefined term, the article is > also insightful but is still too cryptic for me to be able to reproduce the > process to generate a proper custom style (base curves, color matching, > etc.). I am wiling to do so (buy the it8 target etc) and share the result > with the community but I am going to need help. > > On 2017-03-03 15:59, Guillermo Rozas wrote: > >> what you're looking at is the difference between the in-camera Canon >> processing and Darktable's processing. DT has its own way of >> processing the RAW data in the CR2 file that is not 100% the same way >> Canon uses, which produces changes in the final output. Is not that >> one or the other are right or wrong, they're just different. >> >> When importing photos (CR2) into Darktable (2.0.7), >>> colors/contrast/brightness... aren't the same as in the "Gnome Document >>> Viewer" preview (and on the screen of my 80D). >>> >> >> The Gnome's viewer is probably using the JPG preview embedded in the >> CR2 file, and in that case it should look almost the same to the 80D's >> screen. DT takes the real CR2 data and processes it, so it will almost >> always look different (it's also color managed, so there may also be a >> difference there if you profiled your monitor) >> >> I initially had problems with Darktable 1.4.2 where every photo (same >>> format, same DSLR) imported would look pink. I upgraded to 2.0.7 and the >>> problem was gone, that is why I suspect that this might be another >>> darktable-related problem. >>> >> >> Your problem with DT 1.4.2 was probably related to the camera being >> unsupported yet (wild guess). What you have now is probably not a >> problem, just a different look. I had the same "shock" the first time >> I used it, because one is used to the Canon processed look and DT's >> look "different". But after a while I learned to stop looking to >> Canon's JPG as "the" target and perfect processing, and to use my own >> judgement (and DT powerful processing) to decide how the image should >> look like. >> >> So, don't worry! Start playing with DT (and read the manual), and >> you'll soon find out that you can control the final image much more. >> > > Thank you. > > That's what I did after reading through the all the insightful answers > that I received. Now I am really looking forward to create a dedicated > style for the canon eos 80d and to release it. > > CA > > ____________________________________________________________ > ________________ > darktable user mailing list > to unsubscribe send a mail to darktable-user+unsubscribe@lis > ts.darktable.org > >
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