Taking the Light's Temperature
Photography always comes back to the light and the color of the light that illuminates our subjects exerts a profound effect on the resulting image. Visible light can vary from the orange of candle flame to the deep blue of the evening sky, but he human eye has a remarkable ability to compensate for this wide spectrum. We can recognize a white card as being white through a broad color range, but our digital cameras lack our cognitive abilities to interpret visual input. Without correction, a white object captured in the yellow light of an incandescent bulb will be recorded with a yellow tint and the blue sky, illuminating someone in the shade of a building will change the face to a cold sickly blue. Digital cameras offer auto white balance settings (AWB) , using various algorithms to compensate for changes in the color of light, but, as is true of most automatic settings, the adjustments often don't produce the best results. This is one of those situations where the computer in your brain can work better that your camera's microprocessor, so its time to get to work.
Your Light Has a Temperature
|Specturm of Light |
Unfiltered sunlight contains the full spectrum of visible light and as a result tends to produce the most accurate white and color reproduction. This is a good setting when shooting outside in full sunlight, but who actually does that?
Cloudy and Shade:
In both of these situations the light tends to be cooler, as the full
|Abigail in Full Shade|
Indoor illumination from Tungsten light bulbs has a strong yellow
|Tungsten Color Balance|
|Kissing Bridge Tungsten WB|
Fluorescent lighting has a blue/green shade which is warmed using the Fluorescent setting. The color of fluorescent can vary a good deal and it can take experimentation to find the best WB setting.
The light from most flash units tends to most closely approximate sunlight, but can be a bit cool. The flash setting usually tends to slightly warm the image.
Custom White Balance:
The fixed white balance adjustments can provide a good approximation of the correct setting for specific lighting, but they are often imperfect. Some cameras allow fine tuning of the color compensation, but the use of Custom White Balance can be the easiest way to nail the precise adjustment. This option is available on many digital cameras.
|Incandescent Light |
and Tungsten White Balance
Custom White Balance starts with taking a picture of a white or neutral gray card in the same light that is falling on your subject. These cards are available on-line or at your local camera store (remember those?). A clean white piece of paper or anything else which is pure white can serve. I have a card with white on one side and gray on the other. The details vary, but on my Canon 5D II, I display the picture of my white card,
|Custom White Balance|
my camera's menu. I tell the camera to use the current image as the basis for custom white balance and then, any time I select "Custom" for the white balance option, the white balance will return to this setting. Custom white balance is helpful whenever precise control of color is necessary, such as in product photography. Your client will not appreciate getting the color wrong on the Campbell Soup can.
All of this fuss about white balance is especially important if you are shooting in JPEG rather than RAW. Need I say that this is just one more reason that you should shoot in RAW? In-camera white balance settings are of little importance when shooting RAW since all of the color information is preserved in the RAW image. Regardless of the original setting, the white balance can be adjusted in post-processing without any loss of quality. Unfortunately, when shooting in JPEG, white balance is baked into the image file with the loss of a significant amount of color data.
To demonstrate this, I intentionally shot Chesterfield's historic town hall with the white balance incorrectly set to tungsten. I captured the image in both RAW and in the highest quality JPEG and then tried to salvage the images to accurately reflect the overcast lighting. There was no problem readjusting the RAW color balance, but, despite doing everything I could in Lightroom and Photoshop the JPEG image's color remained disappointingly flat and dull.
As can be seen, post-processing color balance adjustments on JPEG files are difficult and result in a poor quality image. If for some totally unfathomable reason you are still shooting in JPEG, there are two things to remember.
- First, don't.
- Secondly, if you do, careful adjustment of white balance in the camera is essential. You really won't get a second chance.
So, when shooting RAW is there any reason to set a specific white balance? I generally keep my camera on Auto White Balance. In most situations this works well as a starting point and then I almost always tweak the color in post. In a few situations such as portraiture or product photography strict color accuracy is important, but for most of my work, precise color matching is not necessary or even desirable. When I am shooting in the golden evening light the last thing I want is for whites to appear pure white. If I used custom white balance from a white card, I would loose all the warmth of the scene. Occasionally I will use the cloudy or shade settings to more accurately reflect the warmth of the "Golden Hours", although when shooting in RAW I can make the same adjustment in post. In post processing I am looking for the colors that best reflect the appearance and feel of the moment.
A Fixed White Balance
There are occasional instances when setting a specific fixed white balance can be helpful. Last week I had a great time shooting in the
|Country Store Light|
Of course Photoshop and Lightroom have powerful tools to adjust