Learning Event 5:
IDENTIFY FILTERS FOR BLACK AND WHITE PHOTOGRAPHY
1.
Now comes the real world. How are filters described? It's really a
"bad news, good news" story.
The bad news is that there is no standard
description for the filters most commonly used with black and white film.
Kodak has used two different methods, and other manufacturers use their own
designations. The good news is it really doesn't matter.
There are only
about six common filter colors generally useful with black and white film:
yellow, yellow-green, green, orange, red, and blue. Precise colors may vary
slightly from manufacturer to manufacturer, but they are usually close
enough not to be a problem. Just keep in mind that the most reliable filter
factors are in the data sheet for the film, not the one that comes with the
filter.
Kodak uses Wratten numbers for describing various filters.
Once
you know that a no. 8 filter is yellow, you can use the filter factor for
any similar yellow filter no matter what its manufacturer happens to call
it.
2.
Here are the most common filter colors used with black and white film,
and some of their applications:
a. Yellow (Wratten no. 8, also called K2 or Y2). This is one of two
filters designed to correct for a black and white emulsion's difference in
sensitivity from the eye's. It reduces the excessive blue and ultraviolet
light present in daylight, to which most films are overly sensitive. If you
take a color picture that has blue sky and clouds, then a black and white
picture of the same subject without a filter, and finally one with a no. 8
filter, the clouds rendered by the yellow filter should stand out against
the sky about the same as they do in the color photo.
The shot taken
without the filter will show a nearly white sky with barely visible clouds.
When shooting black and white outdoor scenes with pan film, especially those
with blue sky, this filter is recommended at all times when you don't wish
to use another filter.
b. Yellow-green (Wratten no. 11, also called X1 or YG1). This is the
other correction filter. But where the no. 8 filter corrects an emulsion to
daylight, the no. 11 corrects for the excessive redness of tungsten
Any lamp which makes light by heating a wire filament
produces tungsten illumination.
Ordinary household bulbs and the old-
fashioned flashbulbs are tungsten. Fluorescent tubes and electronic flash
tubes are not. Just as the no. 8 filter is recommended as a standard filter
outdoors, the no. 11 filter is recommended as standard for all black and
white pictures (on panchromatic film) taken in tungsten light. Look again
at Figure 2-6 to see why these two filters are recommended.
c. Deep yellow or Orange (Wratten no. 15, also called G or O). This
filter is basically the yellow filter in overdrive.
It darkens blue sky
much more than the no. 8, thus making clouds stand out sharply against a
moderately dark sky.
It will also increase the brilliance of sunsets and
will penetrate haze effectively. This filter is also effective in bringing
out the texture of architectural stone, wood, fabrics, sand, snow, etc.,
when they are sunlit and under a blue sky. As you should expect, it will
lighten colors with a lot of yellow or red in them, and will moderately
darken greens.
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