The DARKROOM COOKBOOK, Third Edition

SAFELIGHT
Development by inspection is traditionally done using a Wratten #3 dark-green safelight. This
is not because panchromatic fi lms are not sensitive to green, but because green is the color
to which our eyes are the most sensitive. This means that during the brief intervals that the
safelight is on we get the most bang for our buck. The safelight should be fi tted with a 10- to
15-watt bulb and placed at least 3 feet away if the light is to be refl ected off a wall or ceiling
and at least 4 feet away if it is to be aimed at the fi lm.
Even if a chemical desensitizer has been used, the safelight should not be turned on until
at least halfway through the estimated development time. This is because fi lm looses its sensitivity
as development proceeds. If a desensitizer has been used, the safelight can be left
on when the estimated halfway point has been reached (see Desensitizers, below). Without
the use of a desensitizer, the safelight should only be turned on for brief intervals, 15 to 20
seconds at a time, after the estimated halfway point. Pyro developers aid in desensitizing
the fi lm by hardening the surface of the emulsion as development proceeds (see Pyro and
Development by Inspection, below).
A footswitch attached to the safelight is a good idea in order to avoid early termination of
your darkroom career when you reach for the light switch with wet hands. It will also keep
you from dripping developer across the room and down the wall.
JUDGING DENSITIES
Judging the correct density of fi lm is a matter of experience, and it doesn’t take long to learn.
There are two basic methods: transmission and refl ectance. With either method, there are
two points to remember. The fi rst is to always judge through the base of the negative, not
through the emulsion side. The second is to always judge the highlights, not the shadow
densities. The highlights are the densest areas of the negative image; the shadows are the
thinnest.
Transmission
Development by Inspection 135
Frank Rogers taught me to judge negatives by transmission using the fi nger method. To do
this, develop the fi lm for about half the time you estimate it should require (base this on time/
temperature charts or an educated guess). Hold the fi lm up to the safelight with the base side
towards you. The safelight should be at least 4 feet away and aimed at the sink. Then place
a fi nger just behind the back (emulsion side) of the fi lm. As the fi lm develops, the highlights
will become denser and your fi nger will be harder to see. When your fi nger is just barely
visible, development is complete.
Check the density increase every 1 to 3 minutes, depending on how close you estimate you
are to full development. As completion gets closer, you can begin checking every 30 seconds,
but remember, the fi lm is still sensitive to light, unless a desensitizer has been used; therefore,
only check as often as necessary. You will fi nd that after developing by inspection a few times
you will need to check less as you will be able to estimate the progress of development without
frequent inspection.