The colleges have also been told to teach people to dye clothes black.
The OVEC aims to produce at least 9 million black-ribbon pins for public distribution via city halls and state offices.
OVEC secretary-general Suthep Chitayawong led officials to sign condolence messages for the passing of HM King Bhumibol Adulyadej yesterday at the Education Ministry. Suthep also observed a demonstration of black-ribbon pin-making by students from Thonburi Vocational College.