Excessive gamma correction for the for text layers due to the "Default" blending mode
GIMP version: 2.10.0
Operating System: Windows 10 Pro 1803
Description of the bug
I've recently upgraded from version 2.8.20 to version 2.10.0, and encountered this issue, which I introduced at the IRC channel of gimp (developers' channel), and some people in the channel told me why it was happening, and one of them wanted me to file a bug report at that time--this happened a couple of days ago. The issue is caused by the new blend mode introduced with version 2.9.6 as the below excerpt I took from [ gimp.org/news/2017/08/24/gimp-2-9-6-released/ ] explains:
Since we want to make workflows in linear color spaces more prominent in GIMP, it was time to update the blend modes code. You can now switch between two sets of layer modes: legacy (perceptual) and default (linear). The user interface for switching was a quick design, we’d like to come up with something better, so we are interested in your input.
- The "Default" blending mode, which does the gamma-correction for a better viewing on computer screens may be an improvement over the "Legacy" blending mode, but the default blending mode for text layers should remain as "Legacy" because gamma-correction decreases a text layer's readability significantly, which can be seen in the below images ( which are incidentally the same images I showed to developers in the IRC channel):
- Legacy (linear) blending mode: https://framapic.org/ubc820mHS5J9/gzEXi5qfbJm4.png
- Default (gamma-corrected) blending mode: https://framapic.org/ulcKaCRWv9oe/bXeOiFqK0mta.png
For the above images, the mode is "RGB", the precision is "8-bit integer" & "Perceptual gamma (sRGB)", and the font is Amazon ember font, although the new "Default" blending mode affects every font I tried rather badly. Readability of a text layer can be increased by either manually reverting the layer's blending mode to "Legacy", or by shifting the alpha channel's curve above the x=y line. I think there should be a way to set the default blending mode for all text layers to "Legacy".
- A minor side-issue is the collapsed size of the drop-down menu where the mode for a layer is selected, which can be seen in the below screenshot:
Is the bug reproducible? Always
- Create a text layer, and switch between blending modes.
Expected result: No significant change in text readability
Actual result: Significant decrease in text readability