According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace. I've searched
Ebay, Sphere Research and other sites looking for these.

Anyone have one good for a 3" round CRT or know of a good substitute
material (perhaps from a hobby store)?

TIA,

Steve.
--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA