Maximize the data-ink ratio

Tufte proposes a blunt design test: of all the ink on a graphic, how much of it actually encodes data, and how much is grid lines, borders, shading, or ornament that carries no information? He calls this the data-ink ratio and argues designers should push it as close to one as possible, erasing every mark that isn't pulling its weight.

This isn't minimalism for its own sake — it's a claim about cognition. Redundant or decorative ink competes with real data for the viewer's limited visual attention, so a heavy gridline or a drop shadow behind a bar doesn't just look cluttered, it actively slows down the reader trying to compare values. Tufte's proposed fixes are often startlingly simple: lighten or remove gridlines, let data points imply their own axes, erase redundant labels.

Takeaway: before adding a visual element, ask whether removing it would lose any information — if not, erase it.