White Balance: What is it? And Why does it Matter?

By Patty Hankins & Bill Lawrence

Your eyes are remarkably adaptable. They can adjust to a wide variety of lighting conditions. Anyone who has operated a camera which requires manual setting of shutter speed and aperture will be familiar with thinking about the amount of light available, so even though you can see clearly in situations from dim indoor lighting to bright mid-day sunshine, your camera needs to adjust for the amount of light to avoid overexposing or underexposing your film or digital sensor.

But the amount of light is not the only consideration; what about the color of that light? Again, the eyes (and the brain) can be quite adaptable, so that a scene light by greenish-tinged fluorescent lighting might look the same as one lit by orange-tinged incandescent lighting, but what you think you see might not be what your camera sees.

Light that isn’t pure white is going to affect the colors that your camera registers when you take a photo. Sometimes, this is desirable. Last month, we showed a couple of photos from early in the morning and late in the evening in Arizona, when we were specifically trying to get the landscape photos lit by the “golden” light when the sun is low on the horizon (see below). However, when you want to accurately depict the color of the scene as if it were viewed in white light, you may need to think about white balance.

In film, adjusting for the color of lighting conditions is done using films made for specific light, and by using color correcting filters. Most digital cameras, however, have at least some ability to correct for specific lighting conditions; if you have a digital camera that has this feature, then it may be worth your time to check it out.

Many digital cameras have several common settings. Usually the default is auto white balance, in which the camera will try to estimate the light color based upon the average color in the exposure. Often, this is close enough, particularly in daylight conditions. However, for conditions strongly lit by one type of light source, you might try to match the source to your setting. Many cameras have settings for fluorescent lighting, tungsten lighting, and potentially daylight settings for sunny and for cloudy days. Another good option is custom white balance, in which you photograph a white or gray object in the light you’re going to photograph in, and use this photo to tell your camera how to set the white balance (exactly how you do this depends on he specific camera).

White balance is one reason that we shoot raw files (see January’s newsletter) when we use our digital cameras. Since the raw files are the raw digital sensor output, and not processed to adjust for white balance, we can adjust after the fact when we download the photos to our computer. That way, if we aren’t satisfied with auto white balance or a preset, we can adjust using a custom white balance. For difficult lighting situations, we’ll try to shoot a medium grey card or an object close to grey or white in order to have a reference to adjust white balance. We have a tabletop studio at home to take photos of small objects – to light it we use standard incandescent lights. This gives a very orange photo if not adjusted, but simply shooting a grey card and using this to set a custom white balance lets us correct the color. This lets us use $12 desk lamps (thank you, Ikea) to light our photo studio.

If your camera is set to take jpeg or tiff files, the white balance processing occurs at the time you take the photo, so make sure that you pay attention to your white balance settings.

Look below for examples of different lighting situations and white balance settings.

*************************************************************************************************************

Sometimes, capturing the color of the light can make a photograph better, which is why we show up at odd hours to catch the early morning or late evening light, such as the photo below, taken early in the morning.

Copyright © 2004, Patty Hankins

However, many times we want to show an image as if it was taken in white light, yet when we take a photo, the camera registers the color of light the photo was taken in, even though our eyes and brain interpret the light as white, and we adjust how we think colors appear.  For example, if you're sitting in a room lit by standard incandescent light, does you notice it has a yellow tint?  Below is a photo taken in our "tabletop studio", lit by fluorescent bulbs that mimic standard incandescent light bulbs.  The subject is a "woozle", which we took a picture of so that we could sell it (trying to clear some space in the house).  The files were processed in BreezeBrowser (www.breezesys.com); you can find a brief review of this program on our website.

	This photo was taken in Raw Mode, and then converted using Auto white balance.  The raw photo was actually a little more orange than this, so it did correct the image a bit - it clearly is too orange.  The card attached should be close to  white, as should the background.
	This is just to show what happens when you get the white balance wrong - this is set to daylight white balance, and actually made the color shift worse.  The color balance of the raw image was about half way between this and the photo above.
	This is the same photo using the tungsten setting for white balance, which is the white balance you should be using if you're shooting a scene lit by incandescent lights.  It is still a bit too yellow, and using a custom white balance might work out better, but it is a whole lot closer to what we want than the result from auto white balance.

If we were shooting TIFF or JPEG files, so that the processing was done in the camera rather than the computer, we either would have used the Tungsten white balance setting or used a custom white balance setting for the scene.  What we did was use a medium gray card in a separate photo, so that we could create a custom white balance in BreezeBrowser (though other raw file converters can be used in similar fashion).

This is the woozle with a gray card, which is a neutral colored card, shown using the auto white balance setting.

When converting, we simply clicked on the gray card to let BreezeBrowser know that the card should be neutral .

This is the final woozle photo, using the same custom white balance as the one for the gray card above.  If I didn't have a gray card, I would have tried using the tag to set the white balance, or the background - look for anything neutral gray or white. If you don't have a gray card, think about getting one if you find yourself dealing with tricky lighting situations.  The gray card is one of the cheapest pieces of photographic equipment we own (well, at least one of the cheapest pieces of photographic equipment actually sold as photographic equipment), and can be incredibly helpful.

Not photographing stuffed animals on your work table?  Knowing white balance can still come in handy.  Patty had taken the following photo when her flash misfired, in a building primarily lit by fluorescent lights.

	This photo was an important photo, and it came out blue, because the flash wasn't lighting the scene.  It was shot in Raw Mode, so that we could play with white balance settings.
	Fortunately, the woman on the left was wearing a gray suit.  We simply used this to set the custom white balance.  In a pinch, we could have tried using the white name tags for a custom white balance, or tried using the standard fluorescent light setting. Note, if we hadn't believed in shooting raw files before, this would have convinced us.

Please use your browser's "Back" button to return to previous page,

Or use the navigation bar at the top of the page.