Types of Camera Filter to Choose
Filters are available as gelatin squares,
gelatins cemented between glass, and glass filters. Gelatins might be
the preferable color filter for most uses. They are so thin that
optical problems are few. They will last quite long with ordinary care,
and can be carried in large numbers with very little weight or bulk.
However, they cannot be cleaned and can be easily damaged by
fingerprints and scratching. Also, if you need to work in the wet,
remember that gelatin is water soluble.
Cemented gel-glass sandwiches are both
durable and cleanable, but they may break or separate if dropped, and
if carried in quantity they may be noticeably bulky and heavy.
Polarizing filters are nearly always in the form of glass sandwiches.
Some special filters are available only
in glass with special qualities. In this case, there is no choice of
type, except where the quality of manufacture or the thickness is
involved. Only the best glass filters should be used, and they should
be no thicker than necessary. To clean glass filters, lightly brush off
all dust particles and then breathe on the glass and lightly polish it
with a soft lint-free cloth or lens tissue-just as with lenses.