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Selecting the
Best White
Balance for Nature Photography
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by
Ian Plant
White balance is an
important creative tool for nature photographers.
Without getting too technical, white balance is
a process that determines how color is interpreted
in a digital photograph, and is typically used to remove undesired color casts from
images. Getting the "right" white balance
requires an understanding of how white balance
works. I say "right" in quotes because white balance is
often a subjective artistic choice, especially for
nature photographers.
"Fitz Roy"
—Los Glaciares National Park, Argentina.
Proper understanding
of white balance is critical to correctly rendering
a spectacular sunrise.
What
is white balance?
Not all light sources
produce light equally across the entire
visible spectrum. For example, something lit by
fluorescent lights looks different than something
lit by sunset light. "White balancing" is a process of
correcting the colors of an image depending on the
light source, in an effort to make the colors look
like they were shot in "neutral" light, which is
defined as daylight. When you change your white
balance, you are basically telling your camera to
change the way it sees color.
Color temperature
The key to
understanding white balance is understanding color
temperature, which is actually quite simple. Color
temperature is a measurement of the relative warmth
or coolness of a tone, measured using what is known
as the Kelvin (K) scale. The Kelvin scale is
somewhat counterintuitive, as colors that we
consider to be "cool" (such as
blues) are assigned high color temperatures, whereas
colors that we consider to be "warm" (such as reds and yellows)
are assigned low color temperatures.
Daylight from the middle of the day is considered to be "neutral,"
as at that time the entire visible spectrum
is lit with roughly equal amounts of all colors.
Digital camera white
balance also uses the Kelvin scale, with most cameras using
5200-5500K as their neutral daylight setting.
Lucky for us, the folks who invented white balance
made things more intuitive by "flipping" the numbers
(they didn't really flip the numbers, but for
reasons too technical to bother with here the end
result is that the numbers seem flipped). The bottom
line is that, quite intuitively, a low white
balance setting makes an image cool, whereas a high
white balance setting makes an image warm.
Cameras
have a bunch of preset white balances so that you
don't have to think about numbers at all, but it is
a good idea to understand the numbers even if you
use the presets. Most digital cameras use something
similar to the following presets and corresponding
color temperatures:
|
Preset |
Color Temperature |
|
Tungsten |
2850-3200K |
|
Fluorescent |
3800-4000K |
|
Daylight/Flash |
5200-5500K |
|
Cloudy |
6000-6500K |
|
Shade |
7000-7500K |
Here's a
real world example of the various preset
white balance settings in action:
|
Tungsten |
Fluorescent |
Daylight/Flash |
Overcast |
Shade |
As shown by this series
of images, white balance settings with a lower color
temperature render colors cooler, whereas white
balance settings with a higher color temperature
render colors warmer.
So, for example, a
scene taken in open shade—which
is shade on a clear day—is lit primarily by
light from the blue sky above
and therefore is cool in color. If you set your white balance
to
5500K ("neutral" daylight), then the
camera will not correct for the light and the image
will be rendered with a blue color cast. To keep the
colors in the image neutrally balanced, you need to
choose the
"Shade" preset (or manually set your white balance
somewhere between 7000K and
7500K). This will make the image warmer, removing the
cool color cast.
The image above of
marsh marigold was taken in open shade on a sunny
day, and therefore was lit primarily by light
reflecting from the blue sky above. The version to
the left shows the image taken using the Daylight
preset (5500K) and shows a strong blue cast. The
version to the right shows the image color-corrected
using the Shade preset (7500K).
How
the human eye perceives color
Human
vision, more or less, perceives light coming
from the sun during the middle of the day as
white. Of course, the color of sunlight
changes throughout the day; for example,
sunlight scattered through atmospheric
particles at sunrise and sunset is
a beautiful and exceptionally photogenic red,
which is why nature photographers get so
little sleep. Also, the color of sunlight
can change if it is reflected off of a
colored surface. For example, if you are in
the bottom of a shaded canyon on a clear
day, the light illuminating the shadows is
sunlight reflecting off of the blue sky
above, and as a result is cool in color.
Human
brains are very good at compensating for
these color differences, tending to do an
"automatic white balance" which filters out
color casts. Stare at a colorful sunset for
a while and then look behind you, and for a
few moments you'll see the world as being
quite blue, until your eyes re-adjust. Human
vision seems especially good at filtering
out cooler colors.
For example, a white rock at the bottom of
the shaded canyon I mention above will be
perceived as white, not blue, even though it
is lit primarily by blue light.
How
film renders color
I know, this is an
article about digital photography, so why am I
talking about film? Some historical
context is useful for understanding how white
balance can be used creatively with today's digital
cameras. Besides, there might actually be a few film
photographers still left in the world!
Most color films are balanced for daylight color
temperatures, usually in the range of 5000-5500K.
This neutral daylight
balance can lead to some interesting results. For
example, shooting in open shade results in images
with a strong blue color cast. Shooting at sunrise
or sunset results in images with extremely warm colors,
warmer than the eye would see them.
As a result, one might say that film often renders colors in an
"unrealistic" way; that is, it often
renders colors in a way that is different from how
the human eye perceives those colors.
The fact that you
cannot adjust the "white balance" of film basically
leaves film photographers with two options: correcting
any resulting color casts
using color compensating filters, or using the color
casts to artistic advantage. Back in the day, most
nature photographers chose the latter option. For
example, although film would render sunset colors warmer than
perceived by the eye, the results were so stunning
that most photographers didn't see the need to correct
for the over-abundance of red light. Another example is a photograph of autumn color reflected in a
babbling mountain brook. Although sunlit autumn foliage reflected in the
stream would be rendered as the eye sees it, any
shaded rocks in the water would be rendered with a
blue cast. The savvy nature photographer would
juxtapose these elements in order to
create an image with rich color contrast—not
quite "real," but beautiful nonetheless.
This is important in
the age of digital, as now we can easily correct
color casts by changing our white balance setting—or,
we can use white balance creatively, much as we did
with color casts in the age of film.
"Autumn Reflections"—Adirondack
State Park, New York.
A neutral (Daylight)
white balance was selected to preserve the blue
light appearing in the rushing water and rocks (which are in shadow and lit only by light reflecting
from the blue sky above), rendering the colors in a
"film-like" manner.
How
to set white balance
I'm not going to go
into camera-by-camera specifics regarding how to set
your white balance; consult your camera manual if
you aren't sure how it's done. Rather, I list below
several strategies which you can employ to set your
white balance.
Manual white
balance selection using trial-and-error:
You can set your
white balance manually before each shot by guessing
at the proper white balance setting, taking the
shot, and then reviewing the image on your camera's
LCD to see if you like the results. If the white
balance looks off, then guess again, and so on until
you get it right. Of course, your LCD might not give
you a completely accurate preview,
especially if working in bright conditions when it
might be difficult to see the image. This can be a
time consuming process, one that is not especially
conducive to field work.
Manual white
balance selection using a white balance reference:
This method allows you to use a "white balance card"
or other reference device to set a custom white
balance for each scene. Basically, the device is
neutral in color, and is placed in the same light as
the scene and used to select a white balance that
will render colors in the scene as if neutrally lit. Once again,
this can add time to the picture taking process, and
as such is not especially conducive to field work.
Also, it may not always give you an accurate
rendering of the scene. For example, say you are
photographing a scene lit by the warm red of sunset.
Using a white balance reference in such a situation
will leave you with a white balance setting that
eliminates the overabundance of red light—which
is why you are taking the picture at sunset in the
first place!
Always keep your
white balance on the same setting: Some
photographers simply set their white balance to
Daylight and never look back. While this will render
images in a fashion that is similar to film, as
discussed above the Daylight setting is not
always appropriate, and can create unrealistic or
undesired color casts.
Automatic white balance:
Most digital cameras
allow you to select an "automatic white
balance" mode. In this mode, the camera's processor
tries to pick the best white balance setting for
each scene. In my opinion automatic white balance
actually does a fairly good job, but it doesn't
always get it right, and sometimes acts
inconsistently.
The first method is
somewhat subjective (which is not necessarily a bad
thing), and can be time consuming. The second
method, while perfectly objective, isn't a good
option for certain types of light, and is time
consuming as well.
The third and fourth methods, although the quickest
and easiest, leave you at the mercy of the white
balance setting selected (whether by you or by your
camera). In my opinion, none of these options are
particularly good.
There
is a final option, however, which in my opinion is a
great option for nature photographers trying to
capture fleeting light: shoot digital raw format and
select your white balance after the shot has been
taken, when converting the raw file on your
computer.
"Delicate Arch"—Arches
National Park, Utah.
Some scenes work
best if color casts are retained. The scene above
was bathed in warm sunset light. Removing the color
cast would have reduced the impact of the light, and
rendered the scene in a way that was not perceived
by the eye.
White balance and
raw
conversion
One great advantage of
shooting raw images is that you can
set the white balance when converting the raw file
on your computer. This can be done in a virtually
lossless fashion; that is, when changing the white
balance in your raw converter, you are not
destroying any of the image's data. This is a great
advantage because you don't have to waste precious
time worrying about getting the white balance
correct while in the field. Rather, you can make
your white balance decisions later when processing
the image, leaving you plenty of time to assess
various white balance options. In my opinion, this
is much better than trying to figure out the best
white balance setting when, for example, the sunset of a lifetime
is happening.
So when in the field
shooting, it doesn't really matter what white
balance you select, as you can always change it
later on the computer and not lose any image data.
Keep your white balance set on Tungsten for every
shot, if doesn't matter—you
can change it to Shade, or Daylight, or anything
else later. I keep my camera set on Auto; as noted
above, Auto gets it right much of the time, making
my raw processing workflow a bit easier later on.
Moments in nature are
often quite fleeting, and the last thing you want to
be doing is fiddling with your white balance
before each and every shot. If you can do it later
during the raw conversion process, why squander precious time in the
field? Personally, I never make any effort to set my
white balance before I take a photograph—although
I usually have a pretty good idea of the white
balance setting I will choose later during the raw
conversion process.
You don't have this
same advantage if you shoot JPEGs. When shooting
JPEG format, the camera's processor converts the raw
data into a finished image and then discards the raw
data, so whatever white
balance setting you have selected is applied to the
image. If you later try to adjust the white balance
of the image on the computer, you will
destroy image data. Chances are with most adjustments
you won't notice any degradation of image quality,
but you might notice some banding or other
quality issues with extreme adjustments.
Setting white balance during raw conversion
Making white balance
adjustments during the raw conversion process is
actually quite simple. Every raw converter has its
own way of setting white balance, but they all
operate in essentially the same way. I use Adobe
Camera Raw for my raw conversions, so I'll use it as
a reference. Here's the Adobe white balance palette:
Pretty simple, huh? The top slider
changes the color temperature (notice how it uses
those Kelvin numbers I talked about earlier). Slide
it to the right (increasing the number) and the
image will get warmer; slide it to the left
(decreasing the number) and the image will get
cooler. White balance actually
uses a second variable in addition to color
temperature, "tint," which can be typically shifted
along the green-magenta axis. For the most part,
digital cameras do not allow you to adjust this
variable, but raw converters do. So, the second slider allows you to control the
tint of the image.
By
activating the drop-down menu, you get a number of
preset options:
"As Shot" will render
the scene with the in-camera selected white balance
(whether selected by you or automatically by the
camera). "Auto" will do its best to automatically set
the appropriate white balance in a fashion similar
to the auto white balance mode on your camera. The
rest are the presets we have discussed, whereas
"Custom" is any setting you manually enter using the
Temperature and Tint sliders.
Another way to set
white balance in Adobe Camera Raw is to use the
White Balance Tool, found in the main toolbar, shown
highlighted below:
After selecting the tool, click
on an area of the preview image that should be a
neutral gray or white. The Temperature and Tint
sliders will automatically adjust to make the
selected color exactly neutral. Sometimes the White
Balance Tool works really well, but sometimes it
doesn't, especially if you have selected something that
really shouldn't be neutral or if your scene was lit
by mixed light sources. If you don't like the results,
just manually adjust white balance
until you get something that works.
What
is the best white balance setting?
The best white balance
setting varies from scene to scene and depends
largely on your own personal artistic tastes. I
encourage you to experiment with various white
balance settings for each image, assessing multiple options until
you find the color balance that appeals to you the
most. What follows are some examples
of using white balance creatively.
"Sandstorm"—Mesquite
Flat Dunes, Death Valley National Park, California.
For the image above of
a sunrise sandstorm, the automatic white
balance mode on my camera choose a white balance of
3800K. This rendered the scene as cooler than it
appeared to the eye, cancelling the warmth of the
sunrise light. During the raw conversion process, I
shifted the white balance to the Daylight setting
(5500K), giving the image the golden tones you see
here. The Daylight setting preserves the colorful
sunrise light, although it arguably renders the scene in a
fashion that is somewhat warmer than perceived by the eye
(but faithful to the way color
slide film would render the image).
"Snowstorm"—Bull
elk, Yellowstone National Park, Wyoming.
For this image of a
majestic bull elk hunkering down during a snowstorm, my camera's automatic white balance
rendered the scene at 5600K, doing its job perfectly
by making the snow in
the scene pure white. During the raw conversion
process, however, I choose a white
balance setting that was a bit on the cool side (4500K). I
selected a cooler temperature to convey a forlorn
and cold mood, which I believe not only closely
matches my perception of the scene, but also more
accurately tells the story of the animal and its
surroundings. Blue is very effective at conveying a
sense of cold, and can be used creatively to trigger an
emotional response in a viewer.
"Ancient Forces"—Virgin
River Narrows, Zion National Park, Utah.
Finally, for the image
above of the Virgin River Narrows in Zion National
Park, the scene was lit by two light sources. The first was light
bouncing down into the canyon interior from sunlight
striking sandstone rocks at the top of the canyon.
This light was warm, making the canyon's sandstone
walls glow with orange color. The second was light reflected from the blue sky above,
which is seen in the shaded interior of the canyon.
I choose an intermediate white balance (5000K), one
which preserved both the warm and cool tones of the
scene. Although my eyes "filtered" out much of the
blue light when I was there in person, and therefore
the blues are rendered stronger in the image than
they appeared, this white balance captures the
colors of the scene in a fashion similar to color
slide film. It's not for everyone—that's
why I call it an artistic, and therefore subjective,
choice. Some photographers would set the white
balance to get rid of the blues, leaving the canyon
walls and the water more neutral and the glowing
sandstone a bright warm color, warmer than perceived
by the eye. Because
the scene is lit by mixed light, there is no single
white balance setting that will give you a perfectly
"realistic" rendering; some part will
always be too warm or too cool compared to how the
human eye perceives the scene's colors.
Conclusion
Although white balance
is a purely subjective choice, understanding how it
works is crucial. My best advice is to experiment as
much as possible with different white balance
variations, in the process learning how different
white balance choices affect the colors of a given
scene. This exercise will allow you to
"pre-visualize" white balance choices while in the
field, thus expanding your creative options.
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