Color And Temperature:
What Are These Words Doing In The Same Sentence?
concept of color temperature is an integral part of photography,
and yet many photographers are not really sure what it means.
Color and temperature don't seem to have a direct relationship
with each other, but light sources are often defined in terms
of their color temperature, which is allied with setting the
white balance in digital photography. In addition, the measurement
of color temperature is in Kelvin degrees. What does all this
like Fahrenheit and Centigrade, is a scale for measuring temperature.
Zero degrees Kelvin (this is defined as absolute zero where
there is no molecular movement) corresponds to -459.67? Fahrenheit.
The relationship between color and Kelvin temperature is derived
from heating a blackbody radiator(think of this as a piece
of black metal) until it glows. The particular color seen
at a specific temperature is the color temperature. When the
blackbody is hot enough and begins to emit light, it is dull
red. This is about 2000? Kelvin and it corresponds to the
color we can see in glowing coals in a fire or the red/yellow
lava from a volcano (#1). As more and more heat is applied,
it glows yellow, and then white, and ultimately blue.
All Photos © 2010, Jim Zuckerman, All Rights Reserved
colors radiating from the blackbody are correlated to colors
we are familiar with in our daily lives. The color emitted
from a tungsten lamp in your living room is identical to the
yellow-white glow when the blackbody radiator temperature
is approximately 3200? Kelvin. When the temperature rises
to 5500?, the quality of white light is identical to the color
of the sun at midday (#2). The cobalt blue color of twilight
just before dark is similar to the color of the blackbody
at about 8000? Kelvin.
numbers are used to understand, for example, how flash effects
your images, and may influence your white balance settings.
The color of the light emitted by a flash is rated at 5500?
by many manufacturers; it is designed to imitate noon daylight
(#3). If the flash produces light that is 5800? Kelvin,
it has a slight bluish tinge. If it is rated at 5200?, it
is slightly warmer, or more yellowish, than white light.
film manufactured to give you accurate colors indoors with
tungsten illumination is balanced for 3200? Kelvin. Examples
include Fujichrome 64T and Ektachrome 50. These films are
designed to be used in the yellow-white light of photofloods
that are specifically balanced for 3200?.
film is not relevant to most of us now, a setting of 5500?
Kelvin as the white balance in digital cameras is just like
using daylight film. This means that if you shoot indoors
with tungsten lights, the pictures will have that yellowish
cast just like the interior of the Vienna opera house (#4).
I purposely used a daylight white balance to make the scene
golden. If I had used 3200? Kelvin for the white balance,
the tungsten lights would be reproduced with the correct
color balance (#5). Different cameras indicate this white
balance in different ways. Some will have an indoors setting
while others will show a light bulb icon. More sophisticated
camera bodies allow you to dial in 3200? K. These all mean
the same thingâ€”that you can expect proper colors when
shooting under tungsten lights.
the middle of the day when cloud cover has obscured the
sun, the minute water droplets of the clouds absorb a certain
percentage of the red and yellow wavelengths of light. The
colder end of the spectrum, the bluish wavelengths, pass
through unimpeded. As a result, landscapes and outdoor portraits
will have a slight bluish cast even during midday. This
also happens in thick fog (#6). In deep overcast, the blue
color becomes more pronounced as it did in (#7). This is
a tree stump that had been buried by a glacier for thousands
of years, and in dark conditions under a thick cloud cover
it went an intense blue/cyan when using a daylight film
(this was taken in the 90s). If the cool tonality is unappealing
to you, set the white balance to cloudy. However, if you
like blue tonality in your shots, by photographing at dawn
or twilight, the color can get quite intense. I photographed
a foggy forest in Italy at 6 o'clock in the morning (#8)
on a daylight white balance. Look how blue it is.
photography you can tweak the color temperature in Photoshop
to a certain degree, but it's much easier to work on color
temperature issues in Adobe Camera Raw or Lightroom because
you have so much control. That's one reason why it's so
important to shoot in Raw mode.
photographers use their cameras on Auto White Balance all
the time. I feel this is a mistake especially when shooting
outdoors. AWB wants to convert the golden light of sunrise
or sunset into white light, and this is not what you want.
In fact, it really destroys the beauty of what you're trying
to capture. I would strongly encourage you to take your camera
off Auto White Balance and use instead Daylight WB or 5500?
K. I leave my camera on this setting for everything I shoot
except when I am photographing indoors and using tungsten
lighting (and then I use a Tungsten White Balance setting)
or when I'm shooting fluorescent lights (and then I use AWB).
If you take comparison shots between shooting at sunset with
a Daylight White Balance setting and photographing with an
Auto White Balance setting, you will immediately see the difference.
I think you will agree with me that the Daylight WB setting
is much better.
you shoot in Raw mode, you can tweak the color temperature
in Adobe Camera Raw or Lightroom. However, if you shoot in
JPEG mode, you cannot effectively alter the color temperature
as you might want to do it. Personally, I prefer to not depend
on manipulating color temperature in ACR because I like to
see the rich, saturated golden colors of sunrise or sunset
as soon as I open the images on my computer.