Controlling and using the white balance

Most digital cameras allow you to choose the white balance manually, unlike film cameras. Even if you just leave it on Auto because it is tiresome to set, it is better to learn what it is and how to use it.

1. Color temperature and white balance


Color temperature

As you know, when there is no light we cannot tell what an object looks like, or what colour it is. Humans are one of the few creatures that can distinguish color. An object has a specific color because when light falls on the object, that color wave is reflected while the other colors are absorbed. However, light also has its own color, so an object can look different depending on the light. The color of light is called "color temperature." Why is it not just called "color"? We say a color is red or blue; but each color range is very wide so we need a quantitative measurement. A scientist heated a black bronze ball, and he found that its color changed to red, then white, and finally blue. While he did this, the colors were measured in degrees Kelvin. If your hobby is photography, you have probably had fun taking a picture of a sunrise. When the sun rises or sets, you can enjoy a fantastic moment, because while it's happening the color temperatures are changing all the time.


mountain

Each type of illumination source has its own color or color temperature. In particular, the color temperature of the sun varies depending on the time of day and the environmental conditions. The figure below shows you the color temperatures of illumination devices. Candlelight is red, incandescent light, halogen lamps and sodium lights are orange, daytime sunlight is yellowish, flash light is almost white, sunlight on a cloudy day is bluish, and before sunrise it is blue. To put it simply, low color temperatures tend to be red and high colour temperatures tend to be blue.


tungsten


illumination1 illumination2

The figure above left shows the color temperature of incandescent light. In the case of incandescent light, the color temperature is relatively low so it shows red. The above figure right shows the sky seen from a plane. The air in the sky above the clouds is without moisture or dust, so it shows dark blue. As we have already said, color temperature differs depending on the illumination device, and this can affect the color of the subject, so it needs to be controlled. This colour temperature adjustment is called "White Balance" or "Color Balance". In the case of film cameras, it can be adjusted using different film (daylight or tungsten) and color filters that are placed in front of the lens. With digital cameras, it can be adjusted using the white balance feature


camera film

Figure above shows daylight type film and tungsten film (used for incandescent light).


filter

The above image shows the role of a filter in adjusting colour temperature. When a blue filter is used, most blue light passes completely through, but red colors (complimentary) only pass through partially.

Digital cameras like the NV series use embedded software to adjust the white balance before converting the data stored on CCD or CMOS into PC format. The white balance feature in the NV series has Auto White Balance (AWB), Daylight, Cloudy, Fluorescent_H , Fluorescent_L, Tungsten, Custom set. It may also have more features such as flash mode and figure input mode, depending on the model.


illumination

The image below shows the results for each white balance mode.


balance mode

2. Application of white balance

The concepts of color temperature and white balance have been discussed above, but it is important to use them properly. Their usage is explained in the following for ease of use.


color temperature
[The AWB is being adjusted on an NV8. You can see how to adjust the white balance in Smart Interface.]

Auto White Balance (AWB) produces an effect similar to how the human eye works. Our eyes have their own fine-tuned auto white balance, which ignores small color deviations and recognizes colors that have been 'learned'.

The image below left is a picture taken on a cloudy day, so it seems to have a reddish tint, and the image below right is the same picture taken in Auto mode.


white balance1 white balance2

To choose a color temperature similar to that in film cameras, select Sunlight. Most films are set for daylight, so this setting can give you the same effect as in a film camera. The image below left has been taken in Sunlight mode and the image on the right in Flash mode (slightly red).

To add red, set to Cloudy Day. To add blue, set to Tungsten. On a cloudy day, the color temperature is usually high so it shows blue. When it is set to Cloudy Day, these blue colors have to be partially removed, so red is added. The image below left arbitrarily used Tungsten mode to emphasize blue colors. The picture has a bluish tint because it is shortly after sunset. But in Tungsten mode, the picture can give the feeling of daybreak. The image below right has been taken beneath a sodium light. In this case, if you set it to Cloudy Day, red colors can be emphasized.

To modify the picture, use the RAW file.

If you do not know which setting to use, or it's too much trouble to do it, use the RAW format. In addition to JPEG, support of the RAW format depends on the camera model. The RAW format is the initial format, before the data stored on CCD is converted into a standard format (such as JPEG) through the Analogue-to-Digital (A/D) converter, and the GX-10, GX-1S, GX-1L, or Pro815 format is supported. The RAW format has no white balance data that can be adjusted using embedded software, so you can adjust the white balance on a PC after moving the data.

The image below shows the SAMSUNG RAW converter. Using this, you can change the contrast, sharpness, and saturation, as well as white balance, at will.


raw format

It's probably best if you can handle a graphics program.

Printed materials, TV images, movies, and pictures and images on the Internet are all computer-edited artefacts. The white balance is also adjusted by means of software, so I think editing images using various programmes in a PC is better than using the embedded software, which is limited. If you do this, you can edit colour details as well as white balance.

The figure shows you how the DVD title "Minority Report" was created. The color temperature of the image below left has been changed to that in the image below right.

Using a professional program, you can change the atmosphere of an image, emphasize a specific color, or edit part of the picture. The image below left was taken on a rainy day to show fallen cherry blossom. It has slightly low saturation and a sombre feeling. The image below right has been edited using Photoshop to emphasize the saturation and warm colors.

white balance 9 White balance 10 White balance 11

We usually say that a camera's color is rich or otherwise, and that the white balance seems way off. However, color is subjective and can vary depending on the situation. A photo is a record of a real scene, but it is important to take control of what you are trying to express. It is recommended not just to stay with 'reality' in your pictures, but to analyze images creatively, editing the white balance and using the various features in your digital camera.