Adjustment skills of color temperature and white balance

Shooting is to record images of people and things with cameras and video recorders. Different scenes have different shooting techniques, including night scene shooting, rain scene shooting, building shooting, portrait shooting and so on. Film dynamic art shooting is also a kind of shooting, but it must follow certain principles. The following are the adjustment techniques of color temperature and white balance that I collected and sorted out, which are for reference only and I hope to help you.

Adjustment skills of color temperature and white balance

Light is one of the important factors that affect photography. Light is colored, and no light is colorless. For example, under the light source at sunrise and sunset, whether it is sunny or tungsten lamp indoors, the color effect of the photos taken is very different. This shows a phenomenon that light and color are closely related. So sometimes in order to restore the real light environment, it is necessary to use white balance, and whether the white balance setting is appropriate or not affects the color reproduction quality of photos.

The concepts of white balance and color temperature should be clarified.

1, what is white balance?

The white balance is based on 18% middle gray scale, so that the color of photos taken by the camera in different light environments can be restored to the standard "white" as much as possible. Simply put, it is the process of correcting the color difference of photos.

2. What is color temperature?

Color temperature is the color change that people's eyes feel when light is at different energies. Simply put, it is the color of light with Kelvin (k) as the color temperature calculation unit. We often see different values such as K2000, K3200 and K4000 in the color temperature value. Then, we know that k is the unit of color temperature. How to understand and write down these values? It is good for everyone to understand the following points.

A, related to people: K (Kelvin temperature) was founded by the British physicist Lord Kelvin at the end of 19, and has been named after it ever since.

B. Color temperature phenomenon while the iron is hot: "Suppose a pure black object can absorb all the heat falling on it without loss, and at the same time release all the energy generated by heat in the form of" light ",then it will become different colors due to the level of heat."

The color change of iron after heating can fully explain the above principle. The temperature corresponding to the color of that iron after heating = color temperature. It should be noted that the color temperature is not the degree of heat and cold of light, but a measure of the color components contained in light.

3. The relationship between white balance and color temperature

From the explanation of the above two terms, white balance and color temperature are actually two different concepts, but because the adjustment process of white balance is actually realized by adjusting color temperature, color temperature is a white balance problem for digital cameras and is closely related to each other.

Learn about cool and warm colors and create unique photos.

Because there are too many color temperature values in different environments, I won't make a specific digital list here. You can search "color temperature reference table" on the Internet to get a general understanding. If you feel troublesome, you may wish to remember two points: cold and warm colors and the standard color temperature value in normal sunlight environment.

Color temperature > 5000K, which belongs to cool tone (color is blue) and has the effect of cold atmosphere;

The color temperature is 3300-5000K, which belongs to the middle tone (white) and has a refreshing and clear atmospheric effect;

The color temperature is less than 3300K, which belongs to warm color (red color) and has a warm and steady atmospheric effect.

Distinguishing the hue and atmosphere effect of this color temperature range is conducive to creating more artistic photos and grasping the custom color temperature adjustment. The color temperature value of most standard daylight environments is 5200-5500K K. Simply put, the standard 5400K is low warm and high cold.

In actual shooting, custom color temperature is actually a very interesting function. By adjusting different color temperature values, different artistic effects can be created in the same environment. For example, the color temperature involved in common small fresh styles and retro styles has a great influence on the photo atmosphere. This is why the author did not completely memorize the specific color temperature values of each environment, but only talked about the color tone distinction and effect.

Let's take the following photo as an example. The picture on the left is the original color, which looks very general. The picture shows the next effect after changing the color temperature later. (Of course, besides camera customization, color temperature adjustment can also be done later. This article focuses on the built-in camera, so I won't talk about it later. )

The photo above was taken at 6 pm. At first, the effect of automatic white balance is white, and there is no feeling of warm sunshine in autumn. The second picture is also a completely different atmosphere after listening to the teacher's suggestion to customize the color temperature, and it is also saved later. But to grasp the color temperature, on the one hand, we should distinguish the effects of cold and warm colors, on the other hand, it is aesthetic, and improper use will be counterproductive, as follows:

Common error color temperature mode: 1, the color temperature exceeds the standard; 2. Wrong color choice

Improper control of color temperature does bring people a different feeling, but this feeling is really uncomfortable, let alone aesthetic feeling. Here, the author has a use experience. When you are not sure that your aesthetic sense is correct enough, when using color temperature, try to choose the upper and lower values in the middle, and choose less color temperature values that are too "extreme". We can refer to this statement from the following examples.

From this comparison chart of color temperature effect, the color temperature of K6300-K3700 is relatively acceptable, and the cooling and heating effect is also moderate. But too high or too low numerical shooting effect is obviously a bit excessive. Of course, everyone still needs to combine the subject and the environment to finally decide this "degree" in actual shooting, so shooting more and trying more will slowly find the feeling.

How to adjust white balance

1, rich white balance mode makes you less worried.

At present, almost all digital cameras have at least five white balance modes, such as auto, sunlight, shadow, cloudy, tungsten lamp, white fluorescent lamp, flash and so on. Different brands of cameras have different built-in mode names. Among them, automatic white balance is the most used by everyone. In the normal shooting environment of sunshine, automatic can really meet everyone's shooting needs. In addition to professional photography needs, gray cards will be used.

In some special shooting environments and requirements, you can choose the appropriate white balance mode or adjust the color temperature to obtain more satisfactory shooting results. For example, indoors, the general indoor lighting environment is mainly tungsten lamp and fluorescent lamps. Compared with the environment in tungsten lamp, it is enough to use automatic white balance correction under fluorescent lamp. In tungsten lamp, the images are mostly gray and warm.

For example, the above photo in indoor lighting environment is actually gray, but the color of the photo taken under automatic white balance is obviously yellow and distorted. If it's to show different artistic effects, that's fine. If it is to reflect its authenticity, we might as well choose the tungsten lamp mode. From the comparison photos, the color of dog hair has been well restored.

2. How to adjust the white balance manually?

In addition to a variety of more automatic white balance modes, manual adjustment of white balance will be more accurate and wider. So how to adjust it manually? Operation steps: aim the lens at the gray card or white paper, fill it with the viewfinder picture, shoot with the shutter, and set it as the new white balance standard.

Diligence method: a, gray card. Let the model or himself hold the gray card close to the position of the subject, and point the gray card at the middle angle between the main light source and the camera (for example, if the light source is from top to bottom, the gray card needs to be tilted to the upper light source) to prevent the card from reflecting the light of the camera. In addition, as long as the light source and environment change, it must be re-measured. But at present, the application of grey card is mainly used in professional shooting, including video shooting. In order to ensure the most accurate exposure and color reproduction, automatic white balance is actually enough.

Convenient method: B, white paper. If you say you don't want to spend money on a gray card, or you don't want to take it with you, use white paper (if you don't have white paper, find a pure white object). Compared with the grey card, white paper is also a helpless temporary substitute, and usually white paper is not pure white, so the test based on white paper will have a certain degree of color difference, which can not make the grey card accurate. Of course, in the environment where the color of light sources such as bars and KTV is particularly complicated, white paper still has certain reference value and practical value, at least more reliable than automatic white balance.

D. white balance surround function. Similar to the surround exposure function, you can choose the color temperature range you want in advance, and then take three photos with different white balance effects at a time, which is convenient for you to choose. However, this function is rarely used.

We use the white balance supplementary function to take photos with three different color temperatures in normal sunlight environment, and the specific color temperature range can adjust different color regions of red, blue, magenta and green. It is more suitable for use when you are not sure whether your offset setting is appropriate.

Summary:

1, white balance is the process of correcting the color difference of photos.

2. Color temperature is the color of light. The unit is k (Kelvin)

3. The standard color temperature of sunlight is 5400K, which is low warm and high cool.

4. Manually adjust the white balance: gray card and white paper test.

5. To restore the yellow picture of indoor lighting, tungsten lamp mode is the first choice.

Expand:

White balance definition

White Balance is called white balance in English, and its basic concept is that "white objects can be restored to white under any light source". The chromatic aberration when shooting under a specific light source can be compensated by strengthening the corresponding complementary color. The white balance setting of the camera can calibrate the deviation of color temperature, and we can boldly adjust the white balance to achieve the desired picture effect when shooting.

The white balance setting of digital camera is an important guarantee to ensure the ideal picture color. The so-called white balance is a calculation method of digital image color processing by restoring the color of white objects (producing pure white color effect), and then realizing the accurate color restoration of other objects. If the light emitted by a light source contains the same spectral components as the light emitted by a black body at a certain temperature, it is called a certain K color temperature. If the color of light emitted by a 100 W bulb is the same as that of an absolute black body at 2527℃, then the color temperature of the light emitted by this bulb is: (2527+ 273)K =2800K.

White balance literally means white balance. Then what is white? This involves some knowledge of chromatics. White refers to the visual response of light reflected to people's eyes because of the same proportion of blue, green and red light and a certain brightness. We all know that white light is made up of seven colors: red, orange, yellow, green, cyan, blue and purple, and these seven colors are made up of red, green and blue in different proportions. When the proportion of the three primary colors of a beam of light is the same, it is customarily called achromatic, and the light reflected by black, white, gray, gold and silver is achromatic.

The public's understanding of white is brightness without color components. The white or other colors seen by human eyes are related to the inherent color of the object, the color temperature of the light source, the reflection or transmission characteristics of the object, the visual perception of human eyes and many other factors (please refer to the principles of chromatics). For a simple example, when colored light illuminates an achromatic object, the color of the reflected light of the object is the same as the color of the incident light, that is, the white object is red when illuminated by red light. When two or more colored lights illuminate the achromatic object at the same time, the colors of the object show additive effect. When colored light shines on a colored object, the color of the object decreases. For example, yellow objects appear red under magenta light, green under cyan light, and gray or black under blue light.

White balance effect

In daily shooting, you will encounter various light sources. Different light sources have different color temperatures. Sometimes the pictures taken will have color difference, and white balance is used to solve this problem. White balance has the following functions:

1. Correct the color temperature and restore the color of the object, so that the pictures taken under different light sources are similar to those seen by human eyes.

2. By controlling the color temperature, photos with different color effects can be obtained.

White balance color temperature

Another very important concept, color temperature, should be clarified before understanding white balance. The so-called color temperature, in short, is expressed quantitatively by Kelvin temperature (K). Kelvin, a famous British physicist, believes that if a blackbody substance can absorb all the heat falling on it without loss and release all the energy generated by heat in the form of "light", then it will become different colors due to the level of heat. For example, the thermal stress on the black body will turn dark red when it is equivalent to 500-550℃, yellow when it reaches1050-1150℃, and blue when the temperature continues to rise. The color composition of the light source corresponds to the thermal temperature of the blackbody, and the color temperature of any light is equivalent to the "temperature" when the blackbody emits the same color. This temperature is used to indicate that a certain color light is different from other characteristics, that is, the color temperature. In the process of striking iron, black iron gradually turns red in the furnace temperature, which is the best example of blackbody theory. Color temperature phenomenon is very common in daily life, and I believe people are no strangers to it. Tungsten lamp is yellow because of its low color temperature, and different street lamps also emit different colors. The flame of natural gas is blue because of its high color temperature. At noon, the color temperature under direct sunlight is about 5600K, and it is closer to the indoor color temperature of 3200K on cloudy days. The color temperature at sunrise or sunset is about 2000K, and the color temperature of candlelight is about1000 K. At this time, we can easily find a rule: the higher the color temperature, the bluer the light color; The lower the color temperature, the redder it is. When the color temperature of a certain color light is higher than other colors, it means that the color light is bluer than other colors, and vice versa; Similarly, when the light of one color is bluer than the light of other colors, it means that the color temperature of this color light is higher, and vice versa.

Color temperature is a unit of measurement, indicating the color components contained in light. Theoretically, color temperature refers to the color of an absolute blackbody heated from absolute zero (-273℃). After heating, the black body gradually changes from black to red, yellow and white, and finally emits blue light. When heated to a certain temperature, the spectral component of the light emitted by the blackbody is called the color temperature at this temperature, and the unit of measurement is "K" (Kelvin).

White balance adaptability

Because of the unique adaptability of human eyes, we sometimes can't find the change of color temperature. For example, if you stay in a tungsten lamp for a long time, you won't feel that the white paper under the tungsten lamp is red. If you suddenly change the fluorescent lamp to tungsten lamp, you will feel that the color of white paper is red, but this feeling can only last for a while. The CCD adaptability of the camera is not as good as that of the human eye, so if the color adjustment of the camera is inconsistent with the color temperature of the scene lighting, color difference will occur. So what is white balance? White balance is to offset the color difference under different color temperatures by adjusting the color circuit inside the camera, which is closer to the visual habits of human eyes. White balance can be simply understood as that the standard white shot by the camera lens is still white after circuit adjustment under any color temperature condition. This is a common situation, but not all. In fact, white balance is to make the light reflected to the lens achromatic by adjusting the internal circuit of the camera (changing the balance relationship of the three CCD levels of blue, green and red). If the white balance is adjusted with reddish light, then the image of this color light is achromatic color's, and the scenery of other colors is blue (complementary color relationship).

The working principle of white balance

White balance is a very abstract concept. The most popular understanding is to make the image of white still white. If white is white, then the images of other scenes will be close to the color visual habits of human eyes. The process of adjusting white balance is called white balance adjustment. There are generally three ways to adjust the white balance of equipment in the early stage: preset white balance, manual white balance adjustment and automatic tracking white balance adjustment. Usually, according to the procedure of white balance adjustment, press the white balance adjustment switch, the white balance adjustment circuit starts to work, automatically completes the adjustment work, and records the adjustment results. If you master the working principle of white balance, it will be more targeted and handy to use.

White balance works like this:

There are three CCD electronic coupling elements in the camera, which feel blue, green and red light respectively. Under the preset conditions, the electronic magnifications of the three photosensitive circuits are the same, all of which are 1: 1: 1. The adjustment of white balance changes this ratio according to the adjusted scenery. For example, the ratio of blue, green and red light in the adjusted scene is 2: 1: 1 (blue light is more and color temperature is higher), then the white balance adjustment ratio is 1: 2: 2, and the obvious blue ratio in the adjusted circuit amplification ratio is reduced, while the ratio of green and red is increased, so that the adjusted scene is photographed by the white balance adjustment circuit. In other words, if the adjusted white is a little blue, then the white balance adjustment will become normal. The proportional relationship weakens the amplification of the blue circuit, while increasing the ratio of green to red, so that the image is still white.

Many beginners misunderstand the setting of white balance as simple color temperature fading, thinking that the higher the color temperature, the bluer the image, the lower the color temperature and the redder the image. But whether the real image result is blue or red depends not only on the color temperature in the camera, but also on the color temperature in the shooting scene, and the shooting effect is determined by the difference between the color temperature in the camera and the color temperature in the scene. Here we can directly remember this usage rule: the internal color temperature is higher than the on-site color temperature, and the color of the picture is red; The in-machine color temperature is lower than the on-site color temperature, and the picture tone is blue; The built-in color temperature is equal to the on-site color temperature, and the picture tone is normal. White balance has two most commonly used basic principles in photography. One is to accurately adjust the color temperature, so that the color of the photo can be accurately restored; The other is to creatively use the destroyed balance to reproduce the color of the painting artistically. Experienced photographers often use the second way to create, such as using the blue sky to adjust the balance, so as to get a red and yellow picture. After understanding the working principle of white balance, we will boldly try different effects when using it again, which enriches the camera creation [5].

Another way of thinking is to consider the problem of white balance adjustment. The camera will not "reject" the adjusted scene placed in front of the lens within the tolerance range of white balance adjustment, that is, the lens can adjust the white balance of any scene. In most cases, the white palette (card) is used to adjust the white balance, because the white palette (card) can most effectively reflect the color temperature of the environment. In fact, in some cases, the whiteboard (card) is not white, but more or less blue or other colors. Experienced photographers will also use the blue sky to adjust the white balance, so as to get a picture with red and yellow tones. After understanding the working principle of white balance, we will boldly try different effects when using it again, which enriches the camera creation.

white balance adjustment

In life, the color temperature of sunlight is constantly changing. It can be said that no two places are exactly the same. Different regions, seasons, ground environment, weather, morning and evening will affect the color temperature, and there are a large number of artificial light sources, and the color temperature is not the same. There are three methods for photographers to adjust the white balance: coarse adjustment, fine adjustment and automatic tracking (ATW). Coarse adjustment refers to changing the color temperature filter under preset conditions to make the color temperature close to the factory setting. Fine adjustment of 3200K refers to obtaining more accurate adjustment results for the color temperature in a specific environment with the cooperation of the color temperature filter. Automatic tracking refers to the automatic tracking function (ATW) of the camera, and the camera itself can be adjusted at any time according to the color temperature change of the picture.

White balance preset

Blue-green-red photosensitive balance is set at 3200K color temperature. When the ambient color temperature is 3200K, the camera color temperature filter is set at 3200K, which can restore the scene correctly. When the ambient color temperature is 5600K, the camera color temperature filter is set at 5600K, which can restore the scene correctly. When the ambient color temperature is within the range of 3200K 1000K and 5600K 1000K, the color reproduction acceptable to human eyes can be obtained by using the white balance preset function. Because the color temperature deviation is not big, the picture taken shows subtle color changes. This has advantages. Different living environments will have different colors due to the influence of environmental colors and light differences. If white light is adjusted everywhere, different environments will show the effect of single white light illumination, and this rich color change can be preserved by using white balance preset.

General method of white fine adjustment

In the shooting environment, use a whiteboard (card) to adjust the white balance along the shooting direction. This is a common situation, and there are several very flexible adjustment methods for fine white. Use a standard whiteboard with good permeability, put it in front of the camera, and adjust the white balance in the shooting environment against the illumination direction of the light source or the main shooting direction. Professional cameras will give a color temperature reading, such as 5000K K, if you want to shoot a normal picture, use this white balance result to shoot. In camera creation, sometimes we want to get a picture with chromatic aberration to achieve the purpose of creation. At this time, we can adjust the white balance with any scene. The color temperature of the white scene is complementary to the color deviation of the picture, that is, the red and white picture is biased towards cyan, the green and white picture is biased towards magenta, and the blue and white picture is biased towards yellow. The automatic white balance tracking function (ATW) is adjusted in real time with the change of the color temperature of the scene shot by the lens. If the color temperature of the scene shot by the push lens or pan lens changes (the color temperature of the scene shot by the lens is different from the color temperature of the ambient lighting), the color of the picture will change within a lens. If you push the lens from the panoramic view to the close-up of the face, it is not recommended to use this mode unless there are special circumstances, because the color temperature of the lens will vary with the change of the scene and the skin color of the person in the picture will also change.