Pen to mark molecular weight standards on radioactive blots ???

[Jose de las Heras]

<josmarlangner at yahoo.de> wrote in message 
news:1138976902.815580.263700 at g14g2000cwa.googlegroups.com...
> Hi there,
> could anyone please give a hint where to purchase pens to mark
> unlabelled molecular weight standards on radioactive blots? I don't
> think the ink is radioactive but it somehow gives a signal on the film
> (chemolumi?). I remember that I ordered such a pen about ten years ago
> but I don't remember where.
> Thanks
> Josmar

I used to use a "wax pencil" to mark my blots, label thgem etc... it always 
showed up in the autorads.

Jose