Blue pencil (editing)

[3] An editor-in-chief would use a blue colored pencil to make proofreading marks and final notes on manuscripts before sending it to be typeset and published.

[15][14] Multinational manufacturer AW Faber sold wood and mechanical blue pencils in the late 1800s.

[17] During World War II, bi-color pencils were used to mark troop positions on maps.

[19] In parts of Africa, the "blue pencil" became a metaphor for the censorship and banning of entire books.

[23][24] These cyan colored pencils leave marks that orthochromatic film for offset lithography does not capture,[25] and digital scanners can filter that out.

[26] The un-inked pencil drawings provide a more detailed representation of the original illustrators' work and have blue-pencil notes that sometimes go beyond technical issues to address ideas discussed in the creative process but never used in finished comic books.

[26][23] For similar reasons, some illustrators use red pencils that can be filtered out with xerography or digital scanners.

Comic book artist Rob Guillory used checking pencils to illustrate Chew and Farmhand.