How to use a UV blacklight to check ribbons

[Priedel78]

Hello

sorry for this question but i want to check some ribbons and I never used a blacklight before.

What do I have to do?

It shouldnt glow? or?

[Erich B.]

It is only effective on the white portions of the ribbons. You need to hold the light a distance away from the ribbon, preferably in a darkened room. If the ribbon glows an electric blue color, that's an indicator that a chemical brightener may have been used when the fabric was made. While chemical brighteners were first developed prior to 1945, they were not prevalent in commercial cloth until after the war (1950s). There are many factors that can cause false readings, though, and much original ribbon was and is available on the market.
Erich

[Priedel78]

Thank you very much Erich.
Perfect.

Nicolas