Evening star., 1952-03-23

PAAOtO9A dPAAy VIC 4AoVS 4OoA4ACA AGOW
to diagnose mistakes by recogni-
ton Of typical negative flaws.
These same standards cannot be
applied, however, when we turn to
color photography. In today's
column we will help you interpret
defects which show up In color
transparencies and point out the
probable causes as well as ways
to prevent occurrences.
If you are one of those pho
tographers who rely heavily on
filters, you may some day be hor-
rified to find that number Of
color tfansparencies have an over
all yellow orange, red or green
hue. This Is due to one Of the
most common Of all mistakes, par
ticularly when q beginner In color
photography is involved. This de-
feet is usually caused by q mis-
taken use Of q filter intended
only for monochrome photography.
When you use such a filter when
taking color transparencies, the
transparency viii take on the color
of the filter. The remedy, Of
course, is TO avoid the use Of the
wrong type filters when shooting
color. Keep your color filters sep
arated from those for use with
black and white film. If, in the
course of a days shooting, you
plan to use only color, the safest
thing you can do is leave your
monochrome filters at home,
where you can't pick one up by
mistake.
You probably noticed our use Of
the word usually" in stating that
filter trouble was the cause for
overall color appearance in the
transparency. There are other
causes and you can look for one
Of them If you are positive you
didn't use the wrong filter when
making your exposures.
Effect Of Color Temperature.
For example, should you come
UP with transparency that has
a definite yellowish tinge and the
film used was Ektachrome or
Kodachrome, the trouble probably
stemmed from an exposure OF the
film to q light OF too low q color
temperature. And If either Of
these films Of the daylight type
are used with artificial light with
out the proper conversion filter
the same defect will result. When
using Kodachrome daylight film
with photohood lamps a No. 80
conversion filter will compensate
but your best bet is to use the
right type film for each color job.
Blue flash is the only suggested
artificial light for use with Ekta-
chrome daylight type). for which
no filter is required.
When Ansco color film is ex-
posed to light of@too low q color,
temperature, the transparency
will turn out with pinkish cast.
The use Of No. 10 conversion
filter when shooting AnscoF day.
light color film under artificial
illumination will prevent this
defect.
Another cause for this sort of
trouble is exposure Of the color
film to illumination Of too high
a color temperature. When this
happens the transparency will
have an overall blue hue. In the
case of Kodachrome Type A film
(Which is designed for use with
artificial lights) an exposure to
daylight without the No. IS con-
version filter will cause it to take
on this typical blush appearance.
One Of the Kodak filters, SIC or
BID, should be used when ex-
posing Type A Kodachrome with
white flash lamps. Use CONVEX
sion filter No. 85-B when Type B
Ektachrome is exposed by means
of daylight. Ansco color film Of
the Tungsten type will require q
No. II conversion filter for use
out of doors. Again we recon-
mend the use of the proper film
type with the particular Light
source employed.
Storage and Outdated Film.
A green transparency not caused
by filter misuse may be caused
by other factors. Storage Of any
color film In hot or humid place
can cause this reaction. The use
Of extremely outdated color film
will also result in greeniSh trans
parencies and the same thing can
happen If there is too great q
dalay between the time the film Is
exposed and the time of develop
ment. The answers here are read
lily apparent. Be sure to use fresh
film; store it in a cool place free
of excessive humidity and have
the film developed as soon as
possible after exposure.
If the overall color Is yellow
green with a reversed image and
the transparency is too dense, If
either Kodachrome or Ekta-
chrome were used, the indication
is that the film was exposed
through its base. This happens
when the film holder is loaded
backward with the emulsion side
away from the lens. II Ansco film
is loaded backward and exposed
through the base, the transpar-
ency will be red-brown color,
dense, and with image reversal
If your pictures shot out of
doors are too red or orange the
chances are the fllm was exposed
too early or too late in the day.
The best time to shoot color Aim
outside Is 2-3 hours after sunrise
or 2-3 hours before sunset.
Underexposure Signs.
If the transparency is dark
looking and shadows are excess
sively blue, the trouble is due to
underexpoSure. We recommend
the use of exposure meters that
will take most of the guesswork