Sandra,
My solution to your problem has been to use a fluorescent tube wrapped in
theatre colour filter material, normally used for coloured floodlights or
footlights. I use a 2ft fluorescent tube as it is easily portable with its
fittings attached. I have used Chromagel (or Supergel) #90 "Dark Yellow Green".
It specification sheet shows that almost all its transmission is between 420nm
and 600nm, with a peak at 520nm; its transmission is only 13% and I have wrapped
my tube three times round with this material and secured it with tape. It's
pretty dark when I use this light and I have to sit for a while before I can see
ANYTHING!
I have no evidence that the seeds "see" this light at all - the lettuce
experiment works much as predicted after using this light for a short time.
In US, a main supplier is Strand Lighting Inc, 18111 South Santa Fe Avenue, P.O.
Box 900, Rancho Dominguez, CA 90224. Tel 310 637 7500, Fax 310 632 5519 - they
probably have local agents.
I visited our school theatre and was able to get as much as I needed "off the
roll". Your local theatre will tell you the agent they use for their filter
supplies.
However, for most purposes, I try to avoid using a safe-light at all and fumble
about in a light-proof bag wherever possible.
John
__________________________________________________________________________
| Dr. John Hewitson |
| Berrystead Barn +44 (0)1832 272 209 phone/fax |
| Oundle, |
| Peterborough, PE8 4DY, UK e-mail 100600.70 at compuserve.com |
|__________________________________________________________________________|
(Biology Department, Oundle School)
