You’re not wrong @Terry, I now recall that I turned mine on because I noticed artefacts around lamps in a previous Play Raw when downsampled. If unchecked, it can hurt the quality by introducing jagged lines, dark stripes around objects, or cause moiré.
The blog post for its introduction states this:
For a long time, the default setting was to resize early in the pixel pipeline in order to lower both memory requirements and processing time. This may seem appealing but it has a serious drawback; an early resize throws away lot of precious detail that modules could use at your advantage.
When “Do high quality resampling …” is enabled, darktable processes the image as its full resolution until the very end of the pixel pipeline, and only then, resizes it. In this mode, detail is preserved but more memory and CPU power is required to process the photography.
Source: Upcoming features: New interpolation modes and better resize | darktable
I left it on because it didn’t impact me so much, after all, it’s performed when downsampling so full-res takes the same amount of time. I prefer a slower export over having to do it again by changing the setting for the images where that stuff occurs; then again, every user has different machines and needs. In my case, I always prefer to downscale at the end so it goes with my workflow.
I think the mouse-hover tooltips in export settings could benefit with an overhaul, the way it’s done in the darkroom for module settings, to give an immediate sense of the impact of such features.
User can still go to the manual for further reading, yes, but being warned upfront is key.
Instead of “do high quality resampling during export” a better, in-depth, tooltip could be: “High quality resample processes the image at full resolution, downscale is performed at the end. The process is slower but helps with fine detail and avoiding artefacts or moiré patterns”.
I’m sorry for the wall of text, I tried making it shorter, but I hope it can help people with exporting and downscaling shots like this. Otherwise, feel free to tell me to make another thread about this topic, and I’ll pull this down.
