Demosaic match greens = "local average" trashes the image
Underexposed images with dark subject have a lot of white weird artifacts.
Artifacts look different in darkroom and in exported images (look at screens).
In light table they are seen only at maximum zoom.
Camera: Canon EOS M6
#1 Updated by Mateusz Sebas 4 months ago
I've built current master: 83959cb0e0c86bf0c3cf2ee00834d71a8571a3a4 and I can still see white artifacts.
I think that this issue was not present in July when I bought the canon m6. It started to be visible when I did one of the upgrades of darktable, but I can't say when I did that.
I've tried to build older version of darktable from around July 2017 but I get (and then try to do bisect):
-- Performing Test C_COMPILER_UNDERSTANDS_-Wno-error=address-of-packed-member
-- Performing Test C_COMPILER_UNDERSTANDS_-Wno-error=address-of-packed-member - Failed
-- Performing Test CXX_COMPILER_UNDERSTANDS_-Wno-error=address-of-packed-member
-- Performing Test CXX_COMPILER_UNDERSTANDS_-Wno-error=address-of-packed-member - Failed
I've tried to use gcc 6 (ubuntu 17.10 has gcc 7), but looking at log from build.sh it seems that clang 3.9.1 (maybe older version is needed cause I am on newest ubuntu) is used. I quite don't understand c/c++ environment so its hard for me to debug this and build darktable from July.
#2 Updated by Roman Lebedev 4 months ago
- System changed from Ubuntu to all
- % Done changed from 0 to 10
- Status changed from New to Confirmed
- Subject changed from White artifacts on underexposed pictures on dark places to Demosaic match greens = "local average" trashes the image
Minimal reproducer: default empty history stack, and then in demosaic module set "match greens" to either "local average" or "full and local average".
#4 Updated by Roman Lebedev 4 months ago
I'm guessing the check needs to be ok with negative values too