Colour contrast

Contrast arrives in three forms: light against dark, warm against cool, and saturated against muted. A thumbnail that reads beautifully at full size on a monitor can collapse into mush in a feed. The check takes ten seconds. Shrink it to the width it occupies on your own phone, squint, and see whether the subject still separates from the background. Grayscale it too, which catches two colours that differ in hue while sharing near-identical brightness. On Shorts it matters far less, since most Shorts views come from the swipe feed where no thumbnail shows before playback.