I discovered a bit more than a year ago that the fluorescent looking plastic that is often used in kids toys and for signs is wonderfully fluorescent and stable. If you can't lacate any (try a plastics manufacturer in your town) let me know and I'll secure a chunk for you. ________________________________________________________________________________ Paul Goodwin Image Analysis Lab FHCRC, Seattle, WA On Fri, 22 Sep 1995, Finn-Mogens Haug wrote: > Dear list, > > (I hope this is not too far off topic, but) we have looked mostly > in vain for such standards, specifically "non-bleaching", inorganic, > specimens suitable for 1/ routinely checking excitation level and for > 2/ correcting spatial uniformities of the optical/digital imaging system. > > Reports and handbooks describe the use of uranyl-glass and inorganic > crystals, but the only commercial product we have found contains a > 1-2 mm circular fluorescing area of unknown composition, mounted on a > microscope slide. Price: USD 1400 incl VAT. Expensive? > > A local contact makes Yttrium-Oxy-Sulfide crystals with several discrete > emission/excitation bands for use in microspectrofluorimetry. However, > the powder's granularity may preclude its use in de-calibrating > pixel-to-pixel non-uniformities. > > Names, fax/phone-numbers and e-mail adresses of sources of such standards > would be most helpful, perhaps to others as well. > > > Thanks in advance - > > > > > Finn-Mogens Haug > > Department of anatomy E-mail: [log in to unmask] > Institute of basic medical sciences Phone : +47 22 85 12 67 > University of Oslo Fax : +47 22 85 12 78 >