I just noticed this issue for the first time today. And only on one photo - same exact computer. Considering you’ve seen this escalate, I’d prefer to nip it in the bud
The funny thing is I tried the trick of making a small change. Worked perfectly. Went back in and put the slider back to its original setting. And now the black is in a different spot on the photo - and instead of blocks - it’s a nebulous blob. Moves around each time I makes changes.
Figure I’ll try clearing cache/config and generating the thumbs all at once.
For clarification: If I want to empty the cache and config folders - do I just delete the files within the folders? All the files in those folders? Or remove the actual Darktable folders from within config and cache? Does darktable regenerate them upon relaunch? Regardless, I’d back them up before deleting to be safe.
Not so surprising. You have to find the cause of the issue first. Possibly you have to customize your settings in Preferences → Processing. Clearing the cache is the second step to get rid of precalculated thumbnails containing the black blobs.
Yes. Backup the content of ~/.config/darktable (linux path) first. It contains your databases with all your edits, presets, … Alternatively you can start dt from the commandline and use the switches --configdir /path/to/any/empty/config/folder and --cachedir /path/to/any/empty/cache/folder.
dt creates new config files with default settings (for example dakrtablerc …) and new (empty) databases. Your personal edits and setting are lost of course, as long as darktable does not see your old databases (data.db and library.db) in the config directory you actually use.
The complete cache can be regenerated (based on your data.db and library.db) using the tool darktable-generate-cache. This can take a long time (hours), dependent on the number of edits you have in your database. Make sure darktable-generate-cache terminates with the message Done, otherwise you may have a problem with your database library.db.
Thanks so much for the detailed reply. I’m new to darktable, and appreciate your patience.
Sorry, I should have added more details about my Preferences > Processing settings. Before reading this thread - my Processing tab had some changes from default that I did not personally make. The ‘memory for thumbnail cache’ was set at an odd 71236, which unless I’m reading this wrong, is far more than my computer has. Also, the ‘host memory for tiling’ was set to 8192. I have reset these to the default values listed in the manual (512 and 1500 respectively). Everything else is also set to default settings except: chromatic adaptation set to “modern,” and no ‘auto-apply sharpen.’
I have made backups of the config and cache folders (probably should have skipped the cache folder - I’ll regenerate using the darktable-generate-cache tool). I have been thinking about installing a newer developed build for Mac (3.9.0+35), so this black block/blob issue popping up might be the perfect excuse to give it a try.
