Darktable camera support for Raspberry Pi? No, not yet. Look here, make sure you upload your RAWs.
20180823/https://www.darktable.org/resources/camera-support/
20180823/https://www.darktable.org/2018/06/darktable-244-released/
20180823/https://discuss.pixls.us/t/raw-samples-wanted/5420
20180823/https://github.com/darktable-org/darktable/pull/1201#issuecomment-350458212
20180823/https://www.pentaxforums.com/forums/32-digital-processing-software-printing/356607-pixls-us-raw-file-database.html