Overwhite
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bright screens can read.
Write something, and Overwhite prints it in light instead of ink. On a screen with HDR headroom the words are simply there. On any other screen the same file is a blank card.
The numbers
The card sits at and your words at , a fixed brighter. A screen without headroom renders both as the same white, so the words vanish into the card. The card covers under a fifth of the frame because a full-bleed card at this luminance pins a panel at its full-field limit, where the words clip away with it whatever brightness they ask for.