The Wonderful World Of White Balance
- Aug 22nd. 2012
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- By Thomas Shue
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The Wonderful World Of White Balance
What is White Balance?
The Human eye and brain are an incredibly efficient color calibration. As they work together, they automatically adjust exposure of anything that we are looking at and make corrections to see a properly balanced image. Most importantly the eyes and brain can correct for any color cast. In doing so, anything white, actually looks white, no matter the conditions of the ambient light.
DSLR cameras can’t even come close to correcting color like the eye and brain can. DSLR’s capture information in the seen exactly how they see it. To compensate for difficult lighting conditions we have to select the proper white balance setting to ensure a proper result. Also, in order to achieve optimum color, we have to make adjustments to the camera to match the color temperature of the light falling on the subject in the scene.
Let me offer a simple explaination of light. Light is made up of the primary colors, red, green & blue (RGB). All three colors are represented (in varying amounts) in all light sources. Example, tungsten bulbs have emit more red than fluorescent, which is much more green. The amount of each color present (in a given type of light) is measured as color temperature (in Kelvin – K). Basic knowledge of color temperature unlocks all kinds of expression with light, especially if you have to use gels for color correction (more on color correction in a later post).
If you make images in any mode except RAW (like jpeg or tiff), the color information is baked in during file creation. The Camera runs a program to process the Raw data much like we do in post. However the camera will throw away all of the unused file data and leave you with little room for correction. If the color is off and you shoot jpeg, you just might not be able to fix it. You need to set the proper white balance in camera to make sure the color is correct. At a minimum, set WB to Daylight if shooting in the day light, set to cloudy if its cloudy, etc. By doing this up front, it will lock in a consistent color temperature and won’t shift from frame to frame.
I often hear, “if you shoot Raw, you can fix WB in post”. This is correct, however the image on the LCD is a jpeg. Also, the histogram represents color exposure information based on that LCD jpeg. I say it’s best to make a custom white balance, based on the lighting conditions you are shooting in. If you plan on using anything displayed on the LCD to judge if you got the shot right, then be sure to set a correct WB, so you can make a correct judgment.
So how does White Balance work in the real world, I will show you. Watch this video.
I work with a Canon, but Nikon is almost identical, with respect to WB, so this information is still useful.
Here are the seven WB settings in your camera:
Auto White Balance (AWB)
Auto White Balance evaluates a scene and decided’s the proper white point in it. It works OK as long as there isn’t too much color in the scene, It also has a problem setting the proper WB if there is no actual white for the meter to use as a reference. If the camera chooses wrong the image taken will have a color cast. Also the colors change from frame to frame so it’s very difficult to get a consistent series of images, I personally never use AWB.
Daylight will balance color temperature at close to 5200K. This temp is slightly cooler than the mid day sun. Since shooting at Noon is the worst part of the day, and you won’t be doing that very often, this setting works great for all the rest of the day. Daylight is actually 5600K
We see shaded areas as cooler, also. The color temperature is higher (More blue). Most of the time Shaded areas are around 7000K. Remember this setting is for Open shade not heavy shadows.
Cloudy days have a color temperature around 6000K. Use this setting when the sun is behind the clouds, creating a very even and diffuse light.
Tungsten light has a color temperature of around 3200K, and you use this setting if you see an artificial light source that emits a yellow light. There are filters you can put on your lens to correct for this lighting condition (a blue filter #82). I use filters when I use my film cameras.
Fluorescent light has a color temperature of around around 4000K. There is a problem with Fluorescent lights. There are just to many types in the world. The lights from the 1970′s were green, whereas the newer ones are starting to be day light balanced or 5600K. To Make things worse, all Fluorescent lamps keep changing over time (degrading). It is very difficult to adjust to these if you try to use the Fluorescent setting. I suggest to use “Live View” and adjust to your eye in the Kelvin setting, or to make a custom WB with a target.
Flash WB setting is for the pop up or off camera speedlight. The light is very white so the temperature is right at 6000k. This is an easy one until you start gelling flashes to correct for mixed lighting.
Custom White Balance (CWB)
There should be an angelic chior breaking out in your head, every time to press the shutter to make a custom white balance. It is simple to use and really saves the day. CWB, lets you tell the camera what (in the scene) is supposed to be white. The camera does all of the calculations and does a color shift to make sure what you tell it is white, stays white.
Kelvin or K
Kelvin lets you set the color temperature in 100K increments from 2500k to 10000K. It is a great setting for finding a balance in the scene if you have mixed lighting. Using “Live View” in Kelvin becomes the WYSIWYG (what you see, is what you get) setting of white balance. Kelvin is also great for setting WB for video. Kelvin is my “if all else fails” setting, because I know I can dial in a proper WB if, I have to.
Thanks for taking time to read my blog. I am sorry for the long winded post, but there is a lot of information to cover. If you have any question or thoughts, please use the comment section below. Thanks again. Thomas Shue