Blue pencil (editing)

A blue pencil is a pencil traditionally used by a copy editor or sub-editor to show corrections to a written copy.

Blue pencil

A red and blue pencil
Classification	Editing
Used with	Written copies
Inventor	[data unknown/missing]
Related	[data unknown/missing]

The colour is used specifically because it will not show in some lithographic or photographic reproduction processes; these are known as non-photo blue pencils. For similar reasons, sometimes red pencils are used since their pigment will not reproduce by xerography.

With the introduction of electronic editing using word processors or desktop publishing, literal blue pencils are seen more rarely.

The "blue pencil doctrine" is a legal doctrine in common law countries where some parts of a contract are enforced, but not the entire contract.