When reviewing drawings, parts lists, or other documentation, I use a consistent markup system to keep edits clear and actionable—especially useful when reviewing physical copies or juggling multiple revisions.
Blue is for additions or replacements. Whether it’s a full sentence, a line detail, or just a note, blue means “insert this.” It’s unambiguous and easy to scan later.
Red marks deletions. This can be a strikethrough, a circle, or a brief note like “remove.” Anything in red is out. It keeps cleanup fast and focused.
Black is used for general notes or reminders. These aren’t action items but help track thoughts, context, or things to double-check later.
On physical paper, green is for correcting my own errors—usually when I notice a mistake in a note or calculation. Digitally, I just erase and redo, so green doesn’t show up much unless I’m marking up a scan or PDF.
When checking parts lists, I use green highlighter to indicate components I’ve reviewed and approved. If green isn’t available (especially in the field), I’ll use yellow or another color—but the pen I use to mark changes stays consistent with the system: blue for additions, red for deletions.
If something’s off in the list, I’ll use a different highlight color to flag it, but still apply changes using blue or red.