The document states the minimum values of the coefficient of retroreflection R' for unused retro-reflective sheetings for traffic signs and installations. A distinction is made between two different kinds of sheetings and the minimum values are stated for the different colours according to different angles of view and of light-incidence.
DIN 67520-2:1994 history
2013DIN 67520:2013 Retro-reflecting materials for traffic safety - Photometric minimum requirements for retro-reflective sheetings
2008DIN 67520:2008 Retro-reflecting materials for traffic safety - Photometric minimum requirements for retro-reflective sheetings
1994DIN 67520-2:1994 Retro-reflecting materials for traffic safety; photometric minimum requirements for retro-reflective sheetings for traffic signs