a. Correcting for Too Little Light.
Suppose you get some slides to
copy that are too light or dark.
You can correct these by changing your
You must evaluate the originals for density.
If you determine
the original is too dark, you must increase your exposure.
b. Correcting for Too Much Light. The opposite is also true. If the
original is too light, you must decrease your exposure.
The problem is,
just how much correction in exposure do you need? Generally, you can follow
this rule: compensate by two f/stops for each f/stop the original is off.
That is, to correct an original that is one f/stop underexposed, you must
overexpose the duplicate by two f/stops.
Most slide duplicators have a built-in metering system that may be
used to compensate for over/under exposures.
c. Duplicating "As Is." Make special note of the word "correct." If
you only want to duplicate the underexposed slide, you adjust your exposure
by the same amount that the original slide exposure is off. For example, if
it is determined that an original slide is one f/stop underexposed, then
overexpose the dupe by one f/stop to duplicate it.
d. Correcting Off-Color Balance. To correct off-color balance use the
visual evaluation techniques discussed previously and adjust the standard
filter pack and exposure accordingly.
One of the advantages of duplicating slides is cropping out unwanted
portions of the slide and improving the composition. Vertical slides can be
made horizontal or better framing can easily be accomplished, etc.
cropping, the slide will have to be enlarged to some extent and this will
create a need to increase the original exposure.
Use the normal bellows
extension factor method.
The type of process used will depend, of course, upon the type of material
that is used to make the duplicates. For the most part, you will likely be
using a duplicating film that is compatible with the E6 reversal process.
Always be sure to check first.