White balance is one of the most important aspects in photography and the main parameter of the color image transfer method. It determines the correspondence between the color range of the frame and the object itself, as it is perceived by the human eye. An image with a properly adjusted white balance looks natural.
Features of visual perception
During shooting, the camera lens reacts to lighting differently than the human eye. If you set the white balance correctly, then all the shades in the image will come in line with visual perception. The eye has the ability to adapt, but the camera is not capable of this and transmits colors differently. The human brain begins to process the information received through the visual apparatus based on life experience and distorts reality. For example, he remembers that snow can only be white, and does not notice its different shades if he is not trained. Therefore, there is a suppression of those colors that do not fit the experiment. The camera conveys a more realistic lighting of the subject and its coloration.
Installation Options
A parameter can have several settings:
- before shooting, when the photographer sets it up;
- during the color grading process, when it is determined whether there are irregularities in the white balance, and a decision is made as to whether changes to the color display settings are needed.
It can be installed in a modern digital camera in several ways.
When shooting in RAW format, you can set this setting on the computer:
- In order for the frame preview to be displayed correctly on the screen of the camera itself, it is also necessary to correct the white balance. Modern devices have a special mode that allows you to change the type of frame illumination. The camera then corrects for the desired color temperature.
- Some devices can set the correction in degrees Kelvin - a unit of color temperature. This helps the photographer a lot in the process of studio shooting. If you know in advance the color temperature of lighting devices or measure it with a calorimeter, these parameters can be set when setting up the camera.
Features of color correction with a gray card
There is also a gray card color correction mode. This process is time consuming and negatively affects the efficiency of shooting. But the result with this method is noticeably better than with the standard camera setting. In this mode, the photographer places a special card with a neutral gray color next to the subject. Before shooting, he calibrates the camera against this map.
Color grading using a sheet of white paper does not give a perfect result, because special dyes are used in the production process to whiten it. In the case of using gray for white balance, this color can be guaranteed to be a mixture of pure white and black.
Automatic parameter setting
All settings are made when the average frame is neutral in color and the brightest fragment does not have neutral white. For color correction when using a digital camera, you usually only need to change the gains on certain color channels. For example, if there is not enough blue, you need to increase the gain of that color. Then the picture will look as if it was taken not in the light of electric lamps, but in daylight. This algorithm works well in a certain range of color temperatures and warm lighting. But if the bright color is not pure white, the image will have color distortion.
Color temperature
It is important to know how the color temperature works in principle, in order to understand what its numerical expression in kelvins means. It describes the light spectrum reflected by a completely black body, depending on the temperature of its surface. This body itself absorbs any incident light, neither transmitting nor reflecting it. An approximate analogue of the radiation of this body in everyday life can serve as red-hotincandescent or white incandescent metal or stone. Similarly, black bodies show different luminosities when exposed to different temperatures. It is important to understand that light that appears white does not necessarily contain the entire visible spectrum. For example, 5000 Kelvin is neutral, 3000 Kelvin is orange, and 9000 is blue.
Light fixture features
As the color temperature rises, the color becomes cooler as shorter wavelengths of light carry more energy. Daylight or tungsten lamps create light spectra that almost completely correspond to the luminosity of black bodies. Other sources, such as fluorescent and most energy-saving lamps, are very different. So, the higher the Kelvin number, the colder the light. The standard is 5000 Kelvin, which corresponds to a neutral color. This knowledge will help us understand how to adjust the white balance in a photo.
Setting the parameter in Photoshop for the RAW format
Depending on the image format for color correction, you should use different tools to get the best result. For example, when dragging a RAW photo, Photoshop will automatically open a window with the Camera RAW module. Then you can start analyzing the image and its settings. To work with white balance, select the options at the top of the settings menu. In the dropdown menu, you canfind automatic settings, but it's best to use the sliders in the "Temperature" and "Hue" items. With their help, you can change the white balance in Photoshop without losing quality.
JPEG image processing
Now let's deal with the peculiarities of processing the JPEG format. Open the image in the program and create a new adjustment layer with curves adjustment. Go to the channel with the closest hue to what is causing the white imbalance in the photo. We estimate the range of brightness of the spurious hue, for which we find white or black color in the image. If it is in the middle tones, then we start editing the middle part of the curve. Correction may be required on other channels. You can test yourself with the eyedropper tool by taking a color sample from what seems to be the lightest or darkest place.
