Fine permanent fluorescent marker for blue light I am looking for a fine- (or small-)tipped permanent marker to write on Petri dishes that is visible under a blue light or a transilluminator. It would seem obvious, but it is a nuisance. * The Sharpie Neon series are too thick. * Highlighters and all the arts pens I have tried rub off the polycarbonate. * The red colour from Staedtler lumocolor (black body) shows up faintly —none of the other do— but too faintly. * The Neon series from Staedtler triplus fineliner (gray body, triangular) rub off So I would like to find what solutions other have come up with or if there is a brand that works well. EDIT. This is how the Sharpie series look: ![Sharpie neon colors on transiluminator](

I have had this problem before... this is what I ended up using:

You may have to write on a tape or something so that the ink doesn't come off. (Ink may come off if you incubate plates)