I just installed darktable for the first time (Windows 10) and the first thing I encountered was an issue with text rendering:
Note the colour artefacts (a kind of colour fringing) and blurriness of the letters.
Edit: after publishing this post, I noticed that the artefacts are barely visible here, probably due to rescaling of the image to fit it into the post, so here is an enlarged portion of the original screenshot:
This issue seems to be known (see bugreport here) and another user has provided a workaround here. Unfortunately, I did not understand the workaround but found my own which I want to share here.
It turns out that this has to do with subpixel rendering and more specifically Cleartype, which is Microsoft’s implementation of subpixel rendering. So I tried turning Cleartype off (just search for “Cleartype” in the start menu) but that gave only minor improvements. The thing is, when I turned it back on again, the issue was gone (The text still didn’t look perfect, but more on that below).
My interpretation is that, for whatever reason, my cleartype setting was either corrupted or not well set. As you will notice when you switch cleartype on or off, you can’t just turn the switch but you have to go through a five-step process of clicking on whichever bit of text looks best on your screen. Windows then uses that information to optimize the way it renders fonts on this particular screen. Apparently those parameters where just a bit off and while other programs tolerated the imperfection, darktable did not.
As for the still ugly text: I simply find it somewhat too small (although I have an ordinary display, no UHD) and so I set the variable screen_dpi_overwrite in file darktablerc in C:\Users\<myusername>\AppData\Local\darktable to 140 and voilĂ :
