Introduction
White balance in digital photography is the adjustment of the color temperature and any color casts present in the scene in order to achieve neutral and realistic whites in the final image. In this page we'll explain this concept in an easier way, with pratical examples. White balance won't hold any secrets anymore!
Does Light Have a Color?
The first point to clarify to understand white balance is that light always has a color. In the case of natural light, its color is determined by the atmosphere, which filters the light of the sun.
With artificial light, the color depends on the type of lamp being used, such as LED, fluorescent, or incandescent. The color can also change in the presence of reflective surfaces, such as a painted wall.
The color of light is expressed in Kelvin degrees. The scale was obtained by calculating the color that an ideal perfect black body would take on when heated to a given temperature. As the temperature increases, its visible color would shift from red to blue.
Explaining it as easily as possible, it's the same process that makes a metal heated in a forge emit red light. Honestly, this is a physical concept that has nothing to do with this article; you simply need to know that the color temperature is expressed in Kelvin (K). Take it as a fact.
The human brain compensates extremely well for the color variations, ensuring the best possible visual perception. Digital cameras also have a processor that allows them to detect any color casts so as to produce well-balanced photos.
In some situations, such as under fluorescent lamps, the camera may misread the scene and apply an incorrect color filter. Under fluorescent lamps the photo would probably be shifted towards the green, but there are other cases where the correction may be incorrect, such as a sunset whose atmosphere may be completely ruined by a filter that cancels out the warm light.
All the adjustments made by the camera's processor to reproduce the most accurate light color are what we call white balance.
If you'd like to explore more differences between what the eye sees and how the camera interprets a scene, we invite you to read the article below, where we examine the contrast between observing and photographing:
What Color Is the Light?
Understanding the colors of light is essential for every photographer. The most natural light possible is that of the midday sun with a clear sky, and it has a temperature of 5,500 K. Sunlight becomes warmer as it approaches sunrise and sunset, moving down the Kelvin scale until it reaches around 1,800 K when the sun is closest to the horizon. After the sun drops below the horizon or is covered by clouds, the light tends to cool down, reaching up to 16,000 K during the last light of the day.
Artificial light has a much narrower spectrum. The first example of artificial light is fire, initially in the form of bonfires and later candles. The color temperature of candlelight is about 1,000 K and is considered warm light, as it is psychologically associated with the warmth of fire. Incandescent bulbs or warm LED bulbs have a temperature of around 3,200 K.
The light emitted by fluorescent lamps is around 4,000 K and can create some issues with the automatic white balance of cameras. Although it appears normal to the human eye, in photography it often produces unwanted green color casts. Fluorescent lamps are the long white tubes, what we in Italy commonly call "neon," as well as the type used in some stadiums and in certain professional lighting setups. They are becoming increasingly uncommon.
Cold artificial lights are usually found in car headlights, hospitals, and, more rarely, in home lighting. They generally reach temperatures above 8000 K, although all lights above 6000 K are considered cold light. The term is used because their bluish tones psychologically remind us of the absence of sunlight, snow, and ice.
Light is not only what is emitted directly from light sources; there is also indirect light. This type of illumination can be either filtered or reflected.
Filtered light is light that becomes colored as it passes through a surface. A classic example is light passing through a curtain or the colored glass of a window, such as in churches. This is often atmospheric light, which should not be removed through white balance.
The reflected light is the light that, bouncing off a surface, takes some of its color. An example of reflected light is a room with a large red carpet. When sunlight enters through the window and illuminates the carpet, the entire room will take on a reddish tone thanks to the reflected light. Another example is light reflecting off a colored wall and casting that color onto the side of a subject positioned in front of it.
This kind of color cast is also considered ambient light, and therefore should never be removed through white balance.
How White Balance Works
To counteract the color cast introduced by ambient light, the camera applies a filter of the opposite color. Since white is the easiest reference color for checking tonal accuracy, the process is called white balance.
As you can see in the image below, to counter a bluish cast such as the one typical of dusk, an orange filter is applied. On the other hand, to balance the red cast produced by warm light bulbs, a blue filter must be used.
The purpose of white balance is to bring the whites as close as possible to the ideal temperature of 5500 K, which is considered a standard value. In some situations, this process is less straightforward than expected, for example when mixed lighting is present. In the image below, we can clearly see the different color shades of the various light sources illuminating the night in Cortina d'Ampezzo.
When dealing with mixed lighting, the most effective solution is to search for a balanced compromise, to keep the atmosphere intact. There are situations, such as indoor photography, where some post-production is necessary to achieve an even white balance.
In fact, it should be said that a perfectly accurate white balance is not always the best choice, as we'll see in the next chapter.
Color balance
Not to be confused with white balance, whose purpose is to bring white back to its neutral tone, color balance is used to make colors more evocative, to capture what the photographer saw and felt at the moment of the shot.
As mentioned earlier, when you think of a sunset, the reddish cast of the scene is part of the atmosphere itself. The same applies to the golden light of the sunrise or the blue cast typical of the night. If we leave the white balance set to automatic, we'll probably end up with a photo stripped of most of the atmosphere that the light evokes.
While cameras apply white balance mechanically, without any sense of emotion, modern phones can often recognize the scene and are less prone to errors. Still, you may want to enhance certain colors, as you can interpret the mood far better than a machine, creating a more evocative image.
Let's see together a couple of pictures that have been improved with a color balance. In the photo below, the standard white balance has been shifted toward magenta to emphasize the warm tones of the sunset.
In the photo below, snow covers Mount Tofane, creating a contrast with the orange hues of the trees. The color balance has been shifted toward blue to emphasize the cold tones, to convey a sense of cold to the viewer.
In other cases, color balance can also be useful for removing an unwanted color cast. We had an old phone that forced us to remove an annoying magenta cast that appeared in every photo, regardless of the settings.
Automatic white balance
With automatic white balance, the camera uses an algorithm to estimate the dominant color of the scene and automatically apply the most appropriate white balance, which is almost always perfect. It's very rare to need to adjust the white balance in post-production, but we will talk about it later.
If you are shooting with a professional camera, you can also decide to use the RAW format.
We never get tired of saying it: if possible, always shoot RAW. There are several reasons why this format is preferable. First, it preserves all the unprocessed color information, giving you complete control over color tones during post-production; secondly, it holds far more data related to light, letting you work real magic when tuning exposure in post-processing.
Shooting in RAW definitely requires a bit more effort, but the extra work will be rewarded with better photos. Since this topic is a little out of topic, if you'd like to learn more, we invite you to read our dedicated article; you can find it below:
Manual white balance
Some readers may prefer to avoid learning photo editing, which is mandatory when shooting RAW. If you belong to this category, but you are in a place with difficult illumination, the best choice would be using manual white balance.
Manual white balance consists of selecting, in the settings menu, the correct the lighting conditions in which you are shooting, choosing from a list provided by the camera manufacturer. The default presets are usually:
- Tungsten - 3200 K
- Fluorescent - 4000 K
- Flash - 5500 K
- Daylight - 5600 K
- Cloudy - 6000 K
- Shade - 7000 K
If you activate manual white balance, always remember to change the settings if the light changes, for example, when you're shooting outdoors and the sun comes out of the clouds.
Honestly, it's extremely uncommon to use manual white balance, especially for a beginner. Automatic mode usually works extremely well, but if you're dealing with mixed lighting conditions or with very warm or very cool light sources, you will definitely get better results by manually selecting the correct white balance for the scene you're shooting.
White balance correction via software
In the very rare cases where the white balance results are incorrect, you'll need to fix it via software. Unfortunately, there is no standard procedure: in the computer world there are dozens of programs, and photography is increasingly shifting toward smartphones, where the editing software panorama is even wider.
In this chapter we'll have to approach the topic a bit vaguely; it's up to you to find out the exact procedure for your device. In most software, white balance is simply labeled as temperature or color temperature. In this context, the program will generally make you shift towards the warm tones of the red and the cool tones of the blue.
There are often additional settings, which may be called tint for green and magenta shifts, or skin tone for adjustments of colors specifically related to skin. As mentioned earlier, it will be up to you to play around with the various sliders to understand how each adjustment affects the final result.
If the white balance is correct but the image still looks a bit flat, try increasing the saturation. This will make the colors more vivid without altering their actual hue.
In the previous chapters we highlighted the importance of shooting in RAW, an uncompressed format. The main issue with correcting white balance in photos is that, when images are saved, they are also compressed to reduce file size. This process inevitably destroys some information.
When you shoot in compressed formats, small adjustments are absolutely possible. However, if the image was taken with a completely incorrect white balance due to a mistake in your shooting settings, you won't be able to restore it perfectly. You can achieve good results, but not perfection.
Below you can see a deliberately incorrect photograph. A wrong white balance was set, causing the image to appear extremely shifted toward magenta tones, a violet-red hue.
Now let's correct the white balance by setting it to daylight, which is the correct one. The photo immediately looks much better: the autumn colors appear more natural, and the pine cones take on a more accurate hue. In this case we adjusted the RAW file, so no detail was lost and the color fidelity remains absolute.
In the third image we took the incorrect photo, the violet-red one, and we adjusted the white balance in post-production, but starting from the compressed file. If you look at the pine cones, the result is acceptable, but if you examine the blue background carefully, you'll notice some unpleasant violet color casts, and the highlighted areas on the needles have lost details.
To sum up, try to shoot in RAW, as it allows you to fix even major mistakes. If it's not possible, automatic settings are probably the best decision, as they are very accurate in most cases. If you have to set the white balance manually, try not to make mistakes.
Conclusion
We hope you liked our page about white balance in photography. Before saying goodbye, we would suggest you read all the articles we wrote about photographic technique.
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