Bug 411578 - White Balance changes global luminosity
Summary: White Balance changes global luminosity
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Plugin-Editor-WhiteBalance (other bugs)
Version First Reported In: 6.2.0
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-09-04 06:21 UTC by Alexandre Belz
Modified: 2019-09-11 02:54 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 6.4.0
Sentry Crash Report:


Attachments
Digikam processing 5600K (2.21 MB, image/png)
2019-09-04 06:21 UTC, Alexandre Belz
Details
Darktable processing 5600K (1.70 MB, image/png)
2019-09-04 06:22 UTC, Alexandre Belz
Details
attachment-26640-0.html (2.09 KB, text/html)
2019-09-09 10:49 UTC, Alexandre Belz
Details

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Description Alexandre Belz 2019-09-04 06:21:04 UTC
Created attachment 122480 [details]
Digikam processing 5600K

SUMMARY
Going to lower Temperature decreases the luminosity of the picture.

STEPS TO REPRODUCE
1. Open a JPG picture taken with bulb lamp (yellowish).
2. Change temperature to lower value (remove 1000K for instance) or choose a preset like "200W lamp".
3. Apply

OBSERVED RESULT
the picture looses luminosity. For the preset "200W" it's even going dark & blue !!

EXPECTED RESULT
the picture should change the color temperature but keep the global luminosity. And Presets like 100 / 200W lamp should not give a black/blueish result.

SOFTWARE/OS VERSIONS
Windows: 10 

ADDITIONAL INFORMATION
screenshots attached comparing Digikam and Darktable
Please check if the "component" above is the right one ; I can see "balance" and "WB" which made me hesitate.
Comment 1 Alexandre Belz 2019-09-04 06:22:16 UTC
Created attachment 122481 [details]
Darktable processing 5600K

Darktable processes the White Balance without changing the global luminosity. see attached screenshot.
Comment 2 Maik Qualmann 2019-09-07 22:43:43 UTC
Git commit ec6ed65c8d8eb9925690470e918ad2211fc06898 by Maik Qualmann.
Committed on 07/09/2019 at 22:41.
Pushed by mqualmann into branch 'master'.

implement temperature to RGB code from Tanner Helland
FIXED-IN: 6.4.0

M  +2    -1    NEWS
M  +0    -1    core/dplugins/editor/colors/whitebalance/whitebalancetool.cpp
M  +0    -4    core/libs/dimg/filters/wb/wbcontainer.cpp
M  +0    -9    core/libs/dimg/filters/wb/wbcontainer.h
M  +56   -159  core/libs/dimg/filters/wb/wbfilter.cpp
M  +2    -7    core/libs/dimg/filters/wb/wbfilter.h

https://invent.kde.org/kde/digikam/commit/ec6ed65c8d8eb9925690470e918ad2211fc06898
Comment 3 Maik Qualmann 2019-09-09 06:42:17 UTC
To clear up misunderstandings. The preset list is just to set a color temperature value. Such as. 3000K with a 200W lamp. It is not intended to select the light source that was present during the photo shoot.

Maik
Comment 4 Alexandre Belz 2019-09-09 10:49:29 UTC
Created attachment 122556 [details]
attachment-26640-0.html

Ok, good to clarify.

Can i retry now with weekly build 6.4.0 , to check that global luminosity is not affected anymore ?

BR,
Alexandre

-------- Message d'origine --------
De : Maik Qualmann <bugzilla_noreply@kde.org>
Date : 09/09/2019 08:42 (GMT+01:00)
À : alexandre.belz@live.fr
Objet : [digikam] [Bug 411578] White Balance changes global luminosity

https://bugs.kde.org/show_bug.cgi?id=411578

Maik Qualmann <metzpinguin@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |metzpinguin@gmail.com

--- Comment #3 from Maik Qualmann <metzpinguin@gmail.com> ---
To clear up misunderstandings. The preset list is just to set a color
temperature value. Such as. 3000K with a 200W lamp. It is not intended to
select the light source that was present during the photo shoot.

Maik

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Comment 5 Alexandre Belz 2019-09-09 15:36:06 UTC
Sure Maik, I don't expect Preset exactitude .

Although in theory, it should work like that.
for a camera forced to sun conditions (= calibrated to deliver white @ 6500K sunlight), using 3000K should be OK to compensate the yellowish result in incadescent light bulbs environment...

I'll have a try with the 6.4.0
Can I use the weekly build ?
https://files.kde.org/digikam/

Alex
Comment 6 caulier.gilles 2019-09-09 15:44:58 UTC
Alexandre,

Not yet. I currently patch all bundle to build with ImageMAgick and HIEF support. Windows version is patched and complete build have been started one hour ago. It will be complete in 8 hours if all pass with success.

AppImage is not yet fully patched. I perform last verification. After that I will restart whole AppImage builds. Both bundles will be available in One or two days.

MacOS need more advanced code. It will be available in end of week.

Best

Gilles Caulier
Comment 7 caulier.gilles 2019-09-09 15:49:03 UTC
Alexandre,

Just by curiosity, did you have C++ programming knowledge ?

Gilles Caulier
Comment 8 Alexandre Belz 2019-09-09 15:50:59 UTC
High Gilles, 
yes I did C/C++ programming in my beginings... 15 years ago !
I still remind some bits... :D
Comment 9 caulier.gilles 2019-09-09 17:01:25 UTC
Well, perhaps you can help us with small tasks, as to provide little patches in some processing algorithms for ex.

With some guidances, it's not really complicated. Also, as i can see your email domain is closed with FR, so i can talk with you in French directly, by email for ex.

Gilles Caulier
Comment 10 Alexandre Belz 2019-09-10 06:00:32 UTC
Why not... could be fun.
The only issue i see is that i can allocate 1 hour per week only. That may seem very little to be productive/reactive enough.
(I work as a team manager, very tiring, and when I'm back to home my family life does not let me a lot of time).
Comment 11 caulier.gilles 2019-09-11 02:54:39 UTC
If your free time is limited, well the best way to contribute is to test application and report, comment, check bugzilla entries to find duplicates entries and perform triaging. You will help us a lots to create debugger backtraces with reproducible test cases.

If you need specific help, contact me in French by private mail.

Best

Gilles Caulier