At 05:18 PM 10/2/96 -0400, you wrote:
>I am looking for some help. I am trying to measure the
>glare in a light transmittant microscope. A calibration slide
>of objects with known and varied(prefered) optical density and
>size on clear background is needed.  Any suggection to
>buy such a slide? Please response to me directely, thanks
>in advance.
 
I'm not quite sure what you mean by glare but the simplest
approach would be to photograph a grey scale on Kodachrome
to produce an image the right size for the objective you are
using and then calibrate it by running the slide image through
a micro densitometer.
 
Another fast solution is to overlap two ND filters at right angles
to erach other.  Surrounding the point of overlap will be four
zones of different density as follows:
 
                                                       |
                         zone 1                   |                zone 2
                                                       |
                                                       |     filter
            _______________________________
                                                       |       B
                                                       |
                                                filter|  A
                                                       |
                         zone 3                   |                zone 4
 
Zone one is no filter, zone 2  is filter B only, zone 3 is filter A only
and zone four is filter A plus filter B.  To make this we cut Kodak
Wrattan gel ND filters and mount them under a coverslip, carefully
shimming the corner where there is no filter.  Depending upon the
filter densities the result can be what ever ranges you need.
____________________________________________________________________________
          Tom Gore, Advanced Imaging Laboratory, Biology Department
                         University of Victoria, Box 3020
                         Victoria,  B.C.  Canada  V8W 3N5
      e-mail [log in to unmask]  vox (604) 721-7134   fax (604) 721-7120