A little theory
White balance is an important tool for managing the color palette of a photo. One of the advantages of a living person over a digital camera is that a person sees white objects white regardless of the color of the light source due to the inherent color constancy of human vision. Forming a visual image, our brain uses not only signals directly from the light-sensitive receptors of the eye, but also information about the type of light source, as well as our knowledge of what color an object should be. The digital camera is much more primitive, but it is helped by the ability to adjust the white balance. This is a parameter that allows you to change the color of your photos in accordance with changing lighting conditions. The white balance is used to tell the camera which subject should appear in a neutral tone, i.e. white or gray, under these lighting conditions, and the camera, in turn, shifts all other colors so that the color balance (the relationship between colors) remains unchanged.
Using white balance is easy, although it requires some practice. There is no clear advice here, since white balance is a matter of taste. Use the settings that you like and best match the mood of your picture. White balance can be used with equal success to achieve the most accurate color reproduction, as well as to deliberately distort it for creative purposes.
A little theory
It’s no secret that the color depends on the length of light waves. Longer waves mean red, shorter waves mean blue or even purple. The flame of a candle or low-pressure sodium lamps used in street lamps give a reddish-orange light, because they emit in the long-wave range. The cold light of mercury lamps is caused by their short-wave radiation.
The longer the waves, the easier they penetrate the earth’s atmosphere.
The sun at dawn or at sunset is red, because the light of a low sun falls on the Earth at a very small angle and must travel a much longer path through the atmosphere than during the day. As a result, most of the short waves are scattered and absorbed by the air. This is the reason for the warm light of the Golden hour, which is so loved by landscape photographers and Hollywood Directors.
The higher the sun rises above the horizon, the smaller the layer of air its rays have to overcome and the more short waves reach the earth’s surface, leveling the color balance of daylight and making it white.
To characterize the color tone of the light source, as well as to completely confuse people, the concept of color temperature was invented. It’s a bit counterintuitive, but that’s all modern science.
Color temperature is measured in degrees Kelvin (K) and means the temperature to which it is necessary to heat a completely black body so that it begins to emit light of the same hue as the described source.
Imagine a completely black body … well, I know it’s not that easy. Let the model of an absolutely black body be the burner of an imaginary electric stove. Well-heated, the burner will begin to emit a dull purplish-red light. If you heat it even more (don’t try this at home!), the light will turn yellow, and then, if the power of our stove is not limited, then white, after which the stove is likely to fail. If we could increase the temperature further, we would see that the light takes on a bluish hue.
The spectrum emitted by a completely black body.
Thus, the higher the color temperature, the shorter the light waves and, paradoxically, the colder the color. For example, the color temperature of incandescent lamps is about 3000 K, and the cloudless blue sky is about 8000 K.
When you set the white balance, you tell the camera what the color of the light is overboard, and the camera compensates the color balance based on this data so that the final image looks like it was shot in neutral white light. For example, by setting the white balance to 10,000 K, you let the camera know that the lighting is very blue, and to balance it, the camera adds an orange color. If you lied, and in fact the light is not blue at all, but quite neutral, then the camera, trying to compensate for the imaginary shade, will give you a photo in gold colors.
As you can see, the white balance works quite logically. The higher the temperature – the warmer the shades in the photo, the lower the temperature – the colder the colors. This happens because when you set the white balance, you specify the color temperature of the light that you want to see in the image, and the one that needs to be neutralized.
In addition to the color temperature, lighting is also characterized by the presence of the so-called tint, i.e., the deviation of the color shade in the direction of green or purple. For example, the light of many fluorescent lamps has a faint greenish tint, invisible to our eyes, but clearly visible in photos and giving them an unnatural appearance. The ability to control the color offset eliminates this drawback.
Most cameras have a standard set of white balance presets:
Automatic mode (AWB or Auto)
The camera independently evaluates the color temperature of the lighting and tries to achieve a neutral color rendering. This mode works well in clear weather for open scenes, but objects located in the shadows may turn too blue. This is especially unpleasant when taking portraits. As a rule, when using automatic white balance, I make the colors warmer using fine-tuning, if of course the camera allows you to independently adjust each mode.
Automatic white balance works more confidently if there are white objects in the frame that it can take for a reference. If there is nothing white in the frame, it simply averages the color balance, which is not always good. For example, when shooting a sunset sky, you probably would like to keep its warm, Golden-crimson tones, but your camera will try to neutralize them, aiming for a neutral balance, and make the sky gray and boring.
The use of Auto mode is justified in mixed lighting, when the light from different sources has different color temperature. This is, for example, the lighting of a night city. The camera balances the colors of individual sources so that none of them dominates.
It is used for shooting scenes illuminated by direct sunlight with a color temperature of 5000-5500 K. for my taste, the colors are too cold, and therefore I relatively rarely use this mode. I make an exception for those cases when I want to specifically emphasize cold lighting.
White balance – Daylight
This snow-covered branch of a blue spruce is one of the rare cases when the cold white balance of Daylight suits me completely.
Tricky mode for situations where the sky is clear, but the subject is located in the shade and direct sunlight does not fall on it. In this case, the main source of light is the open sky. The sky is blue, because air molecules, as well as dust particles, scatter the short-wave part of the solar spectrum well. As a result, the color temperature in the shadow reaches 8000 K. the Normal solar white balance would leave everything blue and cold, while the shadow white balance, adding a fair amount of orange color, returns the scene to its natural appearance.
The Shade mode is good when shooting in a background light, since the side of the subject facing you is again lit only by the blue sky. In addition, I use Shade whenever I need to emphasize warm tones, even at the expense of realism. Shooting at sunset is a great example of this situation.
Auto WB. The sun has already risen, but the bridges on the lake shore are hidden from direct sunlight by a wall of forest. The only source of light in this case is the cold blue sky.
I used the white balance Shade to compensate for the excessive blueness.
Something between Daylight and Shade. It is intended for shooting in cloudy weather, when the whole sky is covered with clouds and the color temperature is around 6000 K. However, I use this mode in most cases, including on Sunny days. Both people and landscapes seem more attractive to me in a warm light. If for the sake of the beauty of the frame I need to sacrifice accurate color reproduction, I do it without hesitation.