FreeGEM is the community-maintained, open-source continuation of Digital Research's GEM (Graphics Environment Manager), the 1980s GUI that dressed up DOS and the Atari ST. Like the hardware it grew up on, it fakes its desktop color by dithering — checkerboarding gray (#a8a8a8) and pure blue (#0000ff) in equal measure. Averaged as pixels that blends to #5454d4; averaged in linear light it becomes the gamma-corrected #7a7ad9.
Preview#7a7ad9
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All colors4 · click to preview
Dithered Blue (Averaged)
#5454d4
Dithered Blue (Gamma-Corrected)
#7a7ad9
Stone Gray
#a8a8a8
Blue
#0000ff
Dithered Blue (Gamma-Corrected)
The same dithered desktop, averaged in linear light and gamma-corrected — a lighter, airier blue. The simpler pixel average is #5454d4.