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Film is sensitive to light - but...
Film does NOT see the same light that you and I see. That's true
for ALL film. First of all, a camera, lens and film are NOT intended
to record what you see. That would be an impossibility! Just
think - when you look at a scene on a cloudy day, do you see BLUE light???
Well, most film does! When you're in an office lit by fluorescent
light, do you see GREEN light?? Well most film does! When you
look at a scene, is only PART of it in focus?? Well a camera lens
sees only a PART of a scene in focus.
Film and optics combine to "see" completely differently than your eyes and
brain do. Our brain gets into the act by compensating for different
color light. Film is incapable of doing that. You camera lens
isn't anywhere as complex as you eyes and optic nerves. It couldn't
possibly duplicate what you see. So, let's get rid of the
misconception that we take pictures to record what WE see. The
reality is, we take pictures to record what we want the viewer to see.
We need to understand how film and optics work in order to understand what
our pictures will look like when we get them back.
Boy, it's cold out there!
Temperature affects film. Not Fahrenheit or Celsius, but
Kelvin. Kelvin temperature refers to the "Color"
temperature. Color films are designed to be used in a "temperature"
of light. There is basically one kind of film you're likely to see
- film that's balanced for DAYLIGHT light. There's also film
balanced for tungsten and other light, but you're unlikely to find that in
most camera stores.
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Kelvin temperature is a scale that rates the color of light.
The higher the temperature, the more BLUE in it. The lower the
temperature, the more RED in it. Mid-day sunlight (actually
measured in Washington, DC at noon on the summer solstice) is about
5,500° Kelvin. This is what most
"Daylight Balanced" film is manufactured to record. So, if you
take a picture on a cloudy day (about 6,800° Kelvin), the results
will be very BLUE as 6,800° is considerably higher than 5,500° and
the film is expecting 5,500° Kelvin. Likewise, if you take a
picture lit by a 100 watt tungsten light bulb (about 2,800° Kelvin),
then the film will record it much warmer (with more RED) than you
see it. The reason you can't see the color difference is
because our brains interpret what we see for us and compensate so
we'll see what we expect to see.
So, in order to record colors the way we
want them to be recorded (i.e., the way we see them), we need to
change the color of the light before it reaches the film. We
can do that thru color compensating filters.
Because negative film is subject to
interpretation at printing time, compensation can sometimes be made
by the printer, but again, it's usually a machine making the
decisions and it isn't often they decide correctly!
Here's the same scene using daylight-balanced film with different
lighting: 
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The Kelvin Scale
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Contrast
Not only
can't film see color the way we see color, but it can't capture the same
contrast range that we can see. Most of the time, when we look at a
scene, we can see detail in most everything we look at. Our eyes can
accurately see a scene where there is a 2,000 to 1 contrast ratio
(equivalent to 11 f-stops). In contrast (no pun intended),
color film has a brightness range of about 8 to 1 (about 3 f-stops)
- quite a difference! Some beautiful scenes that you see are not capable
of being recorded on film!! This is especially true of sunsets.
Sunsets may have a brilliant sky but the foreground may be in shadow.
Even though you can see foreground detail when you take the picture, the
camera can't record both foreground and sky. You have to expose for
one or the other. Expose for the foreground, and you will
lose all of the color in the sunset and the sky will just be one bright
area. Expose for the sunset and you can get beautiful color, but the
foreground will be close to black.
This image is a simple example: This is a
picture of some text that is half in full light and half in shadow.
The film was not able to record very much detail in the shadow area,
yet in the actual scene, I could easily read the text in shadow.
This type of picture is very difficult to expose properly because
the film can't see that great of a contrast range. |
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In the following image, everyone who viewed this scene did
NOT see the tree's shadow. But when viewing the image, it is
unmistakable that the tree's shadow is SO predominant! Why didn't
anyone see the shadow when viewing the actual scene??? It's because
the film (slight fib - this was taken with a digital camera - which just
goes to prove that there are few differences between digital and film
photography!) couldn't capture the same contrast range that our eyes could
and compresses the contrast range to where the shadow is darker and the
non-shadow areas are lighter in the picture than our eyes saw it.
You
MUST learn to see what the film sees! |
