Evening star., 1952-03-09
By Alexander ]. Wedderburn
Curctor of Photography
The Smifhsonion Institution

IAnce on the part OF Tie paOLOg-
Irapher. Most defects are trace
able to developer or fixing bath
troubles, although q few may be
attributed to miscellaneous causes
which will also be discussed.
From time to time, in the life
of any photographer, there will
| be occasions when spots, streaks.
fog, etc, win Unexpectedly take
q toll of negatives and prints. The
first thought that comes to mind,
particularly In the cases Of be-
ginners, is that something is
wrong with the film or paper.
This is actually so seldom the
case that when something goes
wrong for us in the darkroom,
we might as well dismiss the
thought and look for the trouble
closer to home. So many checks
and controls are used in the
manufacture of Photographic ma
terials that they are uniformly
reliable.
Stick to the Formula.
Many darkroom troubles begin
with shortcuts we sometimes take
when preparing our processing So
lutions. A pinch of this chemical
and a teaspoon Of that may seem
$50 close to the amount specified
that we feel justified with dispens-
ing with the scales. But this is
one of the worst mistakes that can
be made. Chemical formulas
recommended for certain work are
the result Of years Of research and
experimentation and even the
slightest variation may upset the
balance of a particular formula.
So the best advice is that you
follow the directions supplied by
the film or papermaker in every
detail. Don't omit or substitute.
If you don't have the right ma
terials at hand, postpone your
work for another time. Be sure
to mix the chemicals in the exact
order specified and be equally
certain that the solutions are at
the specified temperature recon-
mended before starting to work.
II the time does come when
you are confronted with darkroom
trouble of one kind or another, it
will help il you are able to recog-
nize the defect, put your finger on
the cause, and take immediate
corrective measures. Let's review
the more common print and mega
tive defects and their causes, and
see what can be done to prevent
occurrences in case they do come
our way.
Trouble With Pinholes.
One Of the most annoying OF
all negative defects Is the pinhole
or small clear spot in the emul-
sion. When the print is made
from a negative having pinholes,
they reproduce on the paper as
tiny black spots on contact prints
and larger black spots when the
image is enlarged. These are a
real problem to the majority of
photographers, because the spots
must be removed by scraping with
a sharp knife or razor blade and
the resulting white area on the
print then has to be filled in with
a pencil or spotting Ink. A re-
TOUGHER can fill in the pinholes
on the negative but few amateurs
are capable Of this kind of work.
Negative pinholes are caused by
air bells or particles Of matter in
the developer that prevent the
solution from coming in contact
with the affected area. They may
be prevented by constantly agitat-
Ing the film during development
and by filtering the solution be-
fore each use.
Prints are also affected by air
bells or dirt particles except that
the defect is characterized by
small round white spots on the
print. The same remedies apply
as described above for the mega
tives.
II your negatives or prints show
q general overall fog you are In
real trouble, for little can be done
to save them. The most common
causes OF fog are due to an unsafe
darkroom. developing at too high
a temperature or too lengthy de-
velopment. If a print or film must
remain long beyond the recon-
mended stay in the solution before
"a satisfactory image is obtained
you can pin the cause of the fog
on this.
] Temperature May Cause It.
In warm weather the solution
Temperature may rise above the
proper level with the same re-
suit. # you have checked of both
OF these as possible causes YOU
had better turn your attention to
the darkroom itself. You may
ldiscover that light is leaking in
TO cause the damage, Or it may be
that your safelight is too close
to tray Of developer. or the SAFE
light may simply be too strong
And remember to keep your Aim
and paper under cover at all times
except when actually working with
it. Overlong exposure to a normal
safelight will eventually cause fog
When stains appear on mega
tives or prints look to the de-
veloper and fixing baths. Stains
will take their toll if the de-
lveloper Is exhausted from overuse
or becomes contaminated by
chemicals from other solutions.
Mixing the developer in water
that Is too hot will also cause
stains. Watch the developer, and