All the comparisons of most software color corrections for the GBC, particuarly, Pokemon Yellow title screen.
On the hardware, Pikachu is not pure yellow like you see in Default Raw form.
GBC-Dev
This one is from this developer from 2000:
http://www.devrs.com/gb/software.php#pict2gb
That’s where some emulators used this for color correction, and it has its own gamma and curves on the grayscales. While the colors are the same on both
Jeff Frohwein‘s Gameboy Hicolour convertor and VBA-M and No&Gba’s gba colors, they have different contrast and gamma or curve adjustment on the whole image, so that’s why they look different from each other. The former has higher gamma and curves. I personally use full range for better contrast.
On VBA-M, you can see that it looks too washout, just as explained above. I did a full range on that too. Before, the blacks are greys and the whites are more dark on GB/GBC than GBA, which is slightly less dark than the white.
GBC-Color, a new shader I encountered. Not made by me, but I believe Monroe from libretro did. It was based on the Gambatte with gamma correction on the color primaries, which looks better than Gambatte’s interpretation. I did adjust the white balance for this colparison and it looks slightly warmer and compares fairly with other shaders.
VBA-Color, it has an adjustment for darkening the gamma just like some emulators do with this color adjustment.
Gambatte’s Color correction. The shader version exist and used the same code as the software option. It’s on by default on the emulator. It looks the same, except since it’s a shader, I can use it on Sameboy and looks identical. On Gambatte, the white isn’t balanced, because the colors are at 255,251,255. That was the same on VBA-M and mGBA.
Super Gameboy snapshot is there to show that it’s more desaturated, even throughout the game in SGB mode.
GBA-Color. I showed three options, and I put Darken=0.0 setting since GBC games are not usually adjusted on the gamma for the original hardware, unless if it includes palettes for GBA like Shantae.
PSP-Colors, I threw it in to compare.
The Gameboy Interface has its own color correction before implenting the shaders I made on Libretro. Here is his settings from Color-Mangler shader:
https://www.gc-forever.com/forums/viewtopic.php?f=37&t=2782&start=625#p38593
NDS-Color is there to compare too and shows a warmer color than GBA.
Sameboy’s “Emulated Hardware” and “Preserve Brightness” are identical on color correction, bot both are identical in this screenshot.
BGB’s color correction is similar to Sameboy, and the option defaults to saturation=0.75 and gamma=2.20, and I just use the exact value to 1 on both to compare. BGB’s default setting made the images brighter and a bit washed out for less saturation and high gamma brightness.
On Conclusion, you would commonly see the Default, Super Gameboy, The GBA-Color, and Gambatte. The GBA, GBC, and NDS are around of how it would look on the reflective screen on first two hardwares. I would recommend using the aforementioned three shaders for the closest color correction without the shaders darkening the image, and Gameboy-Interface is good too.
To have the color space converted from the real hardware to sRGB, it would need to have gamma corrected on the color primaries to looks very similar without dark color samples, like Sameboy and Gambatte did. BGB lacked too, and like I said, setting the gamma to 2.2 may correct the color samples, but the image is too bright. .icc profiles are gamma corrected by default to look bright enough on color primaries on red, green, and blue, and even secondaries like Yellow, Cyan, and Magenta.