Dumping color table entries from the last frame of the &quot;256&quot; color GIF:<p>&gt; gifbuild -d colorBanding_255colorsOn1920pixels.gif  | tail -n 200 | grep rgb | sort | uniq | wc -l<p>&gt; 100<p>What happened here is some sequence of color space conversions with gamma correction added&#x2F;removed that ended up compressing the darks.<p>A true 256 color gray gradient will not display so much visible banding. Just throwing together a naive 256 color gradient in Gimp reveals some RGB triplets with mismatched values suggesting the encoder is doing some odd color space conversion. Even then, it has much less perceptible banding when scaled with nearest neighbor to 1920.<p>I suspect most of the examples stem from improper gamma handling than any true demonstration of the limitations of 8-bit channels.