(08-28-2022, 05:52 PM)ajax Wrote: I probably should have pointed out that this picture came from a raw file. Because GIMP can NOT handle raw files it had to be developed using other software. In this case, that was Canon Digital Photo Professional (DPP). I was actually experimenting with the idea of using DPP to perform minimal processing necessary to produce a file that GIMP could open and then do much more refined editing.
One of my reasons for wanting to obtain raw files from the camera is the increased bit depth used to represent colors. A problem I've always recognized when doing this is that the camera can represent color with higher bit depth than the display devices that are used both for developing/editing the photo as well as the devices used by those viewing the resulting image files. The image files in this case are 16bit png format files.
Precision is one thing, file format is another.
So I can reproduce you problem... When exporting to PNG, the "Save color profile" option is checked , and when you do this the data is exported as linear, with a color profile that de-linearizes it, but is ignored by some image viewers (because 16-bit PNG isn't that common, so not that tested).
When I do so, the image saved without the color profile is displayed correctly, and the one saved with a linear profile is too dark, as expected.
Other apps may display the file correctly (Gimp, obviously, but also Firefox...).