Carl,
Your best bet is probably to use greenhouse shade cloth. You can choose
from a variety of shade levels 25%-90%. I have used several different
suppliers. Specializing in hobbyist greenhouse needs are Charley's
Greenhouse Supply and Lee Valley. Suppliers for the commercial
greenhouse trade are Geiger (in PA) and Maryland Greenhouse Supply.
They have all been very helpful and reliable for my needs both here at
work and at home.
Another option is to check with a theater supply company for the gels
used for theater lighting. Your theater department will be able to put
you in contact with someone local. The company I deal with is here in
Baltimore.
I use theater gels for all of my photosynthesis experiments with colored
light and shade cloth for light intensity experiments although theater
gels do come in neutral gray. Your theater department may even have the
sample booklets provided by the manufacturers. In addition to samples
of the actual gel, they usually contain transmission spectra for the
gel. You can be pretty selective about which wavelengths you shine on
your plants when you use the gels individually or in combination.
Elaine
>>> Carl Pike <carl.pike at fandm.edu> - 2/5/03 2:40 PM >>>
I want to shade some leaves but not with the conventional shade cloth
screen. The neutral density filters I have are small pieces of
glass. Has anyone ever heard of neutral density material that is a
plastic film - like the acetate or cellophane sheets we often use as
colored filters? thanks
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