The DARKROOM COOKBOOK, Third Edition

leak light. What is important is the lens. Use either a process lens made for copy work or an
apochromatic (APO) lens. Either of these will make excellent reproductions.
The other two methods both require a positive image, which is then projected onto
another piece of fi lm of the desired fi nal size using an enlarger. This second piece of fi lm is
developed as a negative.
The fi rst of these two methods involves processing the original fi lm as a positive. The
drawback to this method is that your original 35 mm, 120, or 4 � 5 inch image will always be a
positive should you later wish to use traditional silver-gelatin enlarging techniques. However,
if you are dedicated to contact printing processes then this is the best method to obtain high
quality originals from which to work.
There are a number of ways to process your fi lm as a positive; the easiest would be to
send it to a lab such as .dr5 Chrome Lab (see Resources) and the next would be to purchase
a reversal processing kit from Photographers’ Formulary or Kodak and follow the
directions.
The second method for creating a positive requires an interpositive (also known as diapositive)
to be made from the original negative. The interpositive is made by contact printing
the original negative onto another piece of fi lm.
REVERSAL FILM DEVELOPMENT
Reversal Processing and Enlarged Negatives 139
Reversal processing to create a positive image is possible due to the fact that most emulsions
contain a percentage of silver grains that at normal exposure levels remain unaffected
by both light and development. By developing the normally exposed silver grains and then
bleaching them away it is possible to redevelop the formerly undeveloped grains that remain
to create a positive image.
● The fi rst stage is known as primary development. In this stage, the exposed fi lm is developed
using an energetic developer to ensure that every exposed grain in the emulsion is developed.
At this stage, the fi lm is in the form of a negative.
● The second stage is known as bleaching. This stage uses a silver solvent to dissolve all of the
exposed grains of fi lm from the fi rst stage.
● The third and fi nal stage is known as the reversal stage. This is where the negative is reversed
into a positive. This is accomplished by either re-exposing to light or through chemical reversal
followed by secondary development. The second developer reduces all of the silver bromide not
affected by the initial fi lm exposure and left behind in the second stage. At the completion of
secondary development the fi lm is a positive.
The nature and quality of the fi nal image will be determined by the quantity and structure
of the silver bromide left behind after the removal of the primary silver image during
the bleaching stage. If the primary image was dense, as in an overexposed negative, then the
exposure will have extended well into the emulsion and the image left behind after secondary
development will be thin.