PHC Carl Hinkle
302.308
1/2, 1, 1 1/2, 2.2 1/2, 3, 3 1/2,4,4 1/2, and 5. Use this
table as a guide to help you determine the correct filter.
The principles, also, apply to the use of filters not shown
in the table, such as 0, 1, 1 1/2, 2 1/2, 3, 3 1/2, or 4 1/2.
Figure 11-10 shows the difference in contrast
obtained from one negative using different contrast
printing filters.
When using variable contrast paper and filters, you
must remember the following:
The filters should be clean and in good condition
(not scratched, etc.). Like all filters, they fade and must
be replaced.
The density of filters changes with the different
numbers. Filter numbers 0 - 3 1/2 require a one f/stop
increase of exposure compared to the exposure when no
filter is used. Filter numbers 4 - 5 require a one f/stop
increase compared to the exposure when a 1 - 3 1/2 filter
is used, or a two f/stop increase of exposure compared
to the exposure when no filter is used. For example,
when you make a test print with an exposure of f/8 at 10
seconds with a No. 3 contrast printing filter, and then
make another test print with a No. 4 contrast printing
filter, your new exposure will be f/5.6 at 10 seconds.
It is possible to control local contrast by changing
filters. For example, one possibility is for you to print
an overall exposure with a No. 2 filter while holding
Figure 11-10.–Comparison of a number 0, 2, and 5 contrast printing filter.
back or dodging the sky and then burning in the sky with
a No. 1 filter. When printing with more than one filter,
you should work from a full test print to determine the
best approach.
Study the manufacturer’s directions so you can
use their filter and paper combination to best advantage.
Many of us are guilty of throwing away the
manufacturer’s directions that come with photographic
materials. By maintaining them in a reference book, you
have a tremendous source of information available that
can save time and materials.
Having determined the correct exposure and
contrast, you are now ready to produce the production
prints. Until you become proficient in printing, make
test prints for each negative you print.
By adjusting the lens f/stop, you may use longer or
shorter exposure times than the test exposure time
determined previously, providing they do not become
excessive in either direction. Very short exposures are
not practical. Very long exposures subject the negative
to excessive heat from the printing lamp and also waste
time. Five seconds is the minimum amount of exposure
time that you should use. Twenty seconds is about the
longest exposure time required for normal negatives. A
standard procedure is to change the exposure by varying
the f/stop of the lens to bring the exposure time within
practical limits.
11-14
