Redline
An annotated copy of a design marking exact measurements — spacing, sizes, type styles, colors — prepared as the build spec for engineers.
Example usage
“Redline the card states before handoff; the padding, radii, and disabled colors aren’t guessable from the mock.”
Editor’s note
Inspect panels were supposed to kill the redline — every value one click away — but they report without judging. A measuring tool says 17px; a redline says “16, on the grid, and the 17 in the mock is a mistake.” Redlining is the moment a designer declares which numbers are intentional, which ones scale, and which were never decided at all. That judgment is the spec; the pixels are just where it’s written down.