Hi,

Seems as though the pink colours appear in my image when I disable
'highlight reconstruction'. With this disabled the Green & Blue channels
have a lot less data in the highlights than the red. Enable highlight
recon, and it seems to scale all the RGB to a simple range.

Odd, because I do not get this pink appear when I reduce the highlights
in Lightroom... and I am still using this same .dng file.

Chris


On 2018/04/08 05:34 PM, Guillermo Rozas wrote:
> It may be truth (we need a developer to confirm), but in this case it
> seems to be working like I say. Try it:
> - open a picture
> - over-expose it with the Exposure module
> - try to recover using the shift white point slider on Shadows and
> highlights.
> Doing that, I lose all detail in the highlights. At some points in the
> pipeline there are color space transformations, and that may clamp the
> values to the limits to avoid problems (total speculation)
> Regards,
> Guillermo
>
> On Sun, Apr 8, 2018 at 8:17 PM, Robert Bieber <d...@biebersprojects.com
> <mailto:d...@biebersprojects.com>> wrote:
>
>     Don't quote me on this, but since the pixel values are all floats
>     I'm pretty sure it's possible for one module to push them beyond
>     the "maximum" values and another one to bring them back in with
>     the detail still there, as long as everything ends up within the
>     allowable bounds by the time it gets converted to int
>
>
>     On 04/08/2018 07:11 PM, Guillermo Rozas wrote:
>>     Can you provide the original DNG so people can play with it?
>>
>>     One think you should take into account is that modules in
>>     Darktable are applied in a certain order (bottom to top on
>>     darkroom). In particular, "Exposure" and "Base Curve" come before
>>     "Shadows and highlights". So, if Exposure pushes the info of the
>>     sky past the white point, you can not get it back later (at least
>>     that's how I understand it). Going by the histogram, it looks
>>     like this is what happening to your picture (there are a lot of
>>     pixels close to the right edge): the info was there before the
>>     exposure (and base curve) modules, but not by time you get to the
>>     shadows and highlights module.
>>
>>     Two tips I can give you:
>>     - check the RAW over-exposure indicator (small colors icon below
>>     and to the right of the picture in darkroom). If the area is
>>     really non-recoverable it will show as over exposed in RAW. If
>>     not, there is a way to recover it (not always easy, but the info
>>     is there)
>>     - my first step when editing complex pictures is to use the
>>     exposure and black sliders on the Exposure module to fit the data
>>     exactly inside the histogram (using the normal under/over
>>     exposure indicator). Then I know I'm working with almost all the
>>     info the file have.
>>
>>     Best regards,
>>     Guillermo
>>
>>     On Sun, Apr 8, 2018 at 7:04 PM, Peter Cripps
>>     <pe...@petercripps.com <mailto:pe...@petercripps.com>> wrote:
>>
>>         I've seen similar results to Chris. One of the (few) things
>>         that I've found Lightroom does better than darktable is
>>         highlight recovery.
>>
>>         I have noticed that the darktable histogram doesn't seem to
>>         show content at the far right hand side that does show in the
>>         Lightroom histogram. Don't know if this is relevant.
>>
>>         I hesitate to mention this, since I'm very conscious of the
>>         fact that darktable is entirely created by people working on
>>         their own time. It seems ungrateful to pick out one thing
>>         that isn't perhaps as good as with other paid programs.
>>
>>         Peter
>>
>>
>>
>>
>>         On 04/08/2018 02:51 PM, Chris wrote:
>>>
>>>         Hi,
>>>
>>>         So the shadows & highlights module also does not seem to
>>>         full 'reveal' the detail in the clouds that I know exists...
>>>         it simply darkens the existing pixels that we can already
>>>         see. So not really 'recovering detail' as such.
>>>
>>>         https://www.dropbox.com/s/u3lo4oy9dokdbwh/darkt_04.jpg?dl=0
>>>         <https://www.dropbox.com/s/u3lo4oy9dokdbwh/darkt_04.jpg?dl=0>
>>>
>>>         and pushed further
>>>
>>>         https://www.dropbox.com/s/zih4f434frcxizu/darkt_05.jpg?dl=0
>>>         <https://www.dropbox.com/s/zih4f434frcxizu/darkt_05.jpg?dl=0>
>>>
>>>         obviously I am going to extremes here... but they still just
>>>         do not compare to the clarity revealed from LR.
>>>
>>>         https://www.dropbox.com/s/suw9v3jnsszbsec/lr_02.jpg?dl=0
>>>         <https://www.dropbox.com/s/suw9v3jnsszbsec/lr_02.jpg?dl=0>
>>>
>>>         Thanks,
>>>
>>>         Chris
>>>
>>>
>>>         On 2018/04/08 02:30 PM, Pascal Obry wrote:
>>>>         Le dimanche 08 avril 2018 à 14:25 -0700, Chris a écrit :
>>>>>         Anyway, these are my adventures into highlights in DarkTable.
>>>>         You haven't activate the "shadows & highlight" module, so indeed
>>>>         nothing done for darktable :)
>>>>          
>>>
>>>
>>>         
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>>
>>         
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