Relative intensity has been normalized for each temperature (in Kelvins).Note how 5000 K produces roughly neutral light, whereas 3000 K and 9000 K produce light spectrums which shift to contain more orange and blue wavelengths, respectively. Seems like there are lots of options (White card, grey card, color card), and i have no idea where to begin.ColorChecker White Balance also gives you a way to adjust your digital camera's color sensitivity to exactly match the ambient lighting conditions in effect, change what the camera sees. The perceived color of white changes based on ambient conditionsвЂ”outdoors it is perceived to be cooler, indoors it is perceived to be warmer, and under fluorescent light, greener. Even in a controlled studio environment, this can be a problem. As lighting conditions change, your camera shifts the way it reproduces color, resulting in color shifts in your photos or video footage.

Custom white balance allows you to take a picture of a known gray reference under the same lighting, and then set that as the white balance for future photos. Auto white balance is available in all digital cameras and uses a best guess algorithm within a limited range вЂ” usually between 3000/4000 K and 7000 K. Commonly used symbols for each of these are listed to the left.The first three white balances allow for a range of color temperatures. The following table is a rule-of-thumb guide to the correlated color temperature of some common light sources:Fortunately, most digital cameras contain a variety of preset white balances, so you do not have to deal with color temperature and green-magenta shift during the critical shot. Since photographers never use the term color temperature to refer to a true blackbody light source, the term is implied to be a 'correlated color temperature' with a similarly colored blackbody. This may not seem intuitive, but results from the fact that shorter wavelengths contain light of higher energy.Why is color temperature a useful description of light for photographers, if they never deal with true blackbodies? Fortunately, light sources such as daylight and tungsten bulbs closely mimic the distribution of light created by blackbodies, although others such as fluorescent and most commercial lighting depart from blackbodies significantly.

Alternatively, one could click on a colorless reference (see section on neutral references) with the 'set gray point' dropper while using the 'levels' tool in Photoshop. If the image is still too cool (or warm if going the other direction), you can resort to manually entering a temperature in the Kelvin setting.If all else fails and the image still does not have the correct WB after inspecting it on a computer afterwards, you can adjust the color balance to remove additional color casts. In general, if your image appears too cool on your LCD screen preview (regardless of the setting), you can quickly increase the color temperature by selecting a symbol farther down on the list above. In fact, cloudy could be used in place of daylight depending on the time of day, elevation, or degree of haziness. Some cameras also include a 'Fluorescent H' setting, which is designed to work in newer daylight-calibrated fluorescents.The description and symbol for the above white balances are just rough estimates for the actual lighting they work best under.

These are both inexpensive and reasonably accurate, although custom-made photographic references are the best (such as the cards shown above). An example of a pre-made gray reference is shown below:Common household neutral references are the underside of a lid to a coffee or pringles container. An ideal gray reference is one which reflects all colors in the spectrum equally, and can consistently do so under a broad range of color temperatures. Portable references can be expensive and specifically designed for photography, or may include less expensive household items.

This is because the white balance was set based on the moonlight вЂ” bringing out the warm color temperature of the artificial lighting below. On the other hand, some may prefer to leave the color temperatures as is.Note how the building to the left is quite warm, whereas the sky is somewhat cool. Critical images may even require a different white balance for each lighting region. This approach is usually acceptable, however auto white balance tends to exaggerate the difference in color temperature for each light source, as compared with what we perceive with our eyes.Exaggerated differences in color temperature are often most apparent with mixed indoor and natural lighting. Most neutral references measure reflected light, whereas a device such as a white balance meter or an 'ExpoDisc' can measure incident light (and can theoretically be more accurate).Care should be taken when using a neutral reference with high image noise, since clicking on a seemingly gray region may actually select a colorful pixel caused by color noise:Under mixed lighting, auto white balance usually calculates an average color temperature for the entire scene, and then uses this as the white balance.

White Balance Card