I’m on Kubuntu 18.10, with an Nvidia graphics card.
I finished work on a photo in GIMP, and exported to PNG. The resulting image looks different depending on the software I use to view it.
Gimp has no color management enabled, and the image itself is using no embedded/assigned profiles, etc. I exported to regular 8bpp PNG.
Having dealt with this kind of thing before, my first thought was that it was a color calibration thing: I use custom calibration profiles I generated for my monitors. But I don’t think that’s it: setting them all to default profiles, or playing with the gamma slider through the nvidia X server settings, whatever I do affects the monitors, of course, but the differences between the image viewers remains the same. So it seems like it isn’t caused by monitor profiles or nvidia driver issues (e.g. one program using a certain rendering pipeline vs another not, etc.) ?
Gimp and feh look the same, and what I’m considering/wanting to be “correct”.
Firefox shows the image as brighter, especially in the low ranges.
Geeqie and gwenview look the same as each other (bad): much brighter image, and with a noticeable color shift. Like, this isn’t subtle.
Here’s a screenshot of feh vs gwenview to illustrate. (Feh window is overlapping the gwenview window.) (Note: you can ignore the halo around the edge of the overlapping window border: that’s obviously just window manager decoration.)
What the heck is going on here? I read some years ago about Firefox using a slightly unusual but arguably good alternative sRGB profile… but this dramatic difference among apps is alarming. Are they all inventing their own gamma curves and profiles?
I feel like this is likely user error but I can’t figure out how! The whole reason I use monitor-based correction rather than per-program color management is to avoid this kind of thing, yet here I am again.
Any help? Thanks in advance!