been eliminated from the original pack so you would adjust your exposure
b. Subtracting from the Filter Pack.
When working with filter packs
for slide duplicating, the primary rule is to subtract from the filter pack
the complement of the viewing filter and the same density. Of course, there
will be situations where you cannot subtract and must add.
your filter pack for neutral density whenever you must add filtration to the
(1) Exposure adjustments for changes in the standard filter pack can
be easily determined by following the exposure factors given in figure 6-4.
(2) Once you establish a standard filter pack and a standard
exposure, your work becomes a little easier because you use these standards
to copy slides, that is, if your slides have good density and color balance.
Unfortunately, many of the slides that you will be required to duplicate
will be less than ideal in quality. Off-color and poor-density slides fall
in this category.
Factor for Kodak CC and CP filters