Evening star., 1952-07-06
By Alexander J. Wedderburn
Curator Of Photography
The Smithsonian institution


Color processing has become so
simplified in recent years that
many photographers are turning
out their own transparencies. The
margin for error is much narrower
in color processing than in mono
chrome and occasionally we find
some rather odd-looking trans
parencies as the result of our
mistakes. Today we will give you
IA number of clues that will help
track down defects found in Ekta-
chrome transparencies which are
due to errors in processing.
Those who are apt to have the
most trouble with their color films
are the old hands who have been
developing black and white films
for years. This may seem odd but
the truth G6 that many of the
experts" have discovered that
monochrome film chemistry is
rather flexible. Consequently they
have experimental and added a
pinch of this and pinch of that
to the recommended formulas.
weighed their chemicals more by
guess than by scale. and have
been careless about temperature
control of the solutions. In most
cases this disregard for specif1ca-
tionS has done little to discourage
the practice because there is much
that can be done to salvage a
negative that isn't up to par. It
can always be doctored up or cor
rected for when prints are made.
But when these old timers try
this approach with color film
they don't get away with 1t.
There simply isn't the same lati-
tude and If you wind up with a
|mottled or otherwise deficient
color transparency you are stuck
with it. You can't 60 back and
work it up in the darkroom and
attempts to correct for poor color
when printing usually fail to give
even a reasonable approximation
Of the colors Of the original sub
|ject
Follow Directions.
The best way Gin fact the only
way to be successful at color
Aim processing is to literally fol-
low every direction Of the manu-
facturer to the letter. If you do
so three is no good reason why
you shouldn't be able to produce
Ektachrome or other transpar-
encies of first quality. To avoid
confusion we will discuss today
only defects that occur in Ekta-
chrome color film due to errors
of processing. Other films will
be discussed later.
Let's suppose you find that a
batch Of your transparencies have
emerged from the final process
ing step with an overall greenish
tinge. If you are satisfied that
this did not result from other
causes than those encountered in
the darkroom. you may discover,
on checking back, that you didn't
give a full reversal exposure. Too
bad this time but on the next
lot you can make sure that they
receive a reversal exposure ac-
cording to directions. If you are
positive that your reversal expo
sure was on the nose, then look
for the trouble in another direc-
ton. A greenish transparency is
sometimes the result Of made
quate treatment in the bleach
bath. This may be due to re-
moval before the chemical action
Is complete or because the solu-
ton was exhausted or weak. Re-
currence may be prevented by fol-
lowing directions or renewing the
solution.
We have been referring to q
true green appearance. II your
transparency, on the other hand,
has q blue-green or blush cast
you must look for other causes.
Should the Aim have been proc
esSed for a shorter time than
that recommended you can bet
that this was the cause. If the
temperature of the solution was
lower than that called for. you
can believe that Is the trouble.
"Eager-beaverism," to coin word,
is occasionally the cause Of this
blue or blue-green look. Some
darkroom workers insist on wash
ing the film between each opera
ton even though this was not
recommended by the Aim maker
and such a washing between the
hardener and the reversal expo
sure will give this result. Moral:
Do just what you are told to do
no more, no less.
Another cause for a greeniSh
Aim is found when some one mixes