colored light filters

jb189 John_M_BROWNING at UMAIL.UMD.EDU
Mon Oct 9 06:53:17 EST 1995


Sources for light filters:

1. Theater Service and Supply Corporation, 1792 Union Avenue, Baltimore, MD
21211, (301) 467-1225.  Request roscolene acetate gelatin filters.  Order
medium green #874, medium red #823, dark urban blue #866.  Was about $3.35 for
20X24" sheet.  I checked the percent transmittance on the Theater Service
filters from 400-700 nm (I don't know if there is transmittance below or above
this range and my spectrophotometer is average).

2. Kodak Wratten Gelatin Filters, can be purchased from VWR.  I have not
used these, but they are probably the best.  The percent transmittance is from
Kodak ("Kodak Photographic Filters Handbook" from Saunders for $14.95 plus
postage - phone: 716 328-7800). The Kodak filters are expensive.  From VWR, the
red and green are about $50 each for a 6" sheet and the blue is about $125 for
a 6" sheet). The red is Kodak #25 (VWR 170 6811), green #58 (VWR 170 6852),
and blue #47B (VWR 170 7058).

                          Percent transmittance
                  Theater Service             Kodak
                red     green   blue    red     green   blue
        400nm   2       2       13      -         -      16
        425     2       2       30      -         -      47
        450     2       2       41      -         -      36
        475     2       9       28      -         1      9
        500     2       24      11      -         18     1
        525     2       36      3       -         53     -
        550     2       22      2       -         38     -
        575     3       9       2       -         12     -
        600     6       5       2       72        2      -
        625     19      4       2       87        -      -
        650     40      2       2       89        -      -
        675     67      2       2       89        -      -
        700     79      2       2       90        -      -


John Browning
Plant Biology Department
University of Maryland College Park
jb189 at umdd.umd.edu



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