On 2012-12-31 00:28, Eckhart Pedersen wrote: > On 2012-12-30 23:20, Markus Jung wrote: >> The base curve combines three adjustments: Sensor nonlinearity, gamma >> and due to the way how the base curve is created, vendor specific >> in-camera-processing. To build a neutral base curve without the vendor >> characteristics, you need to have at least direct sensor access (-> >> custom firmware). It is quite obvious why we do not have neutral base >> curves ... Regards, Markus > I neglected to make this clearer in my previous message.
1) Sensors record light linearly, but the eyes do not perceive it as such, thus the gamme curve is required. The gamma curve is a standard curve however, and not really sensor specific. 2) Because sensors are not 100% reproductions of our eyes and each type is different from another, they record light *slightly* different than our eyes, and therefore each sensor needs a specific profile, which ends up being the input profile for a given camera. These two factors are combined in the translation from RAW image to JPEG image. To mention them as three separate factors as you have done (sensor nonlinearity, gamme, and vendoc specific processing) is wrong according to my knowledge. It is possible that I have misunderstood something, if so, please enlighten me. But if I am correct, a standard gamme curve with a correct input profile should definitely be enough to yield natural colors. If it is not, the input profile is either incorrect, or the software is written wrong. Again I wish to repeat that I mean no offense, I simple present the facts as I understand them. If I am wrong, I would be very happy to be corrected. > I apologize for not letting this matter rest, but I still do not > understand... > > According to what I know, there are two major differences from a RAW > file to a OOC jpgeg file. > > The first is that the RAW file needs some camera/sensor specific > interpretations, which are taken from the input profile. > > The second is that the RAW file is linear, while the JPGEG file > already has (standard!) gamma curve applied. > > A combination of (standard!) gamma curve plus input profile should > thus give a natural image. If it does not, something must be wrong > according to my knowledge. > > If there is a third factor, please explain what this is to me. > > I apologize if you think this thread annoying, I just wish to > understand who is wrong, and where exactly the error is. Thank you for > your patience! > > Regards, > Eckhart Pedersen > ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnmore_123012 _______________________________________________ Darktable-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-users
