[net.rec.photo] plexiglass

sasaki@harvard.UUCP (Marty Sasaki) (02/19/86)

The reason that plexiglass is bad to shoot through is that it
scratches easily. The scratches diffract the light that goes through
them and generally degrades the image. Glass is better because it
doesn't scratch as easily.

Plexiglass actually transmits more light than glass and doesn't have
the green tint that glass has.
-- 
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  Marty Sasaki				net:   sasaki@harvard.{arpa,uucp}
  Harvard University Science Center	phone: 617-495-1270
  One Oxford Street
  Cambridge, MA 02138

hagerman@friday.DEC (02/21/86)

x

Is there or isn't there a weird effect when light goes through
plexiglass?  I made a contact print frame once with a new, scratch-free
piece of plexiglass about 1/4 inch thick.  Contact prints made with
it came out *very* bad, with lots of strange things at the edges of
objects in the pictures.  I changed to a regular piece of glass
about the same thickness, and things became normal.  I thought that
maybe there were more internal reflections or something...

Doug Hagerman

billw@Navajo.ARPA (William E. Westfield) (02/21/86)

Stressed plastics will do all sorts of weird things to the polarization
of a light source, which may or may not have any effect on picture
taking or using it in contact printers.  More likely is that
plexiglass is easier to deform into non-optically-flat surfaces.

BillW