White balance is one of the most important aspects in photography and the main parameter of the color image transmission method. It determines the correspondence of the color gamut of the frame made and the object itself, as the human eye perceives it. An image with a correctly adjusted white balance looks natural.
Features of visual perception
During shooting, the camera lens responds to lighting differently than the human eye. If you adjust 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 conveys colors differently. The human brain begins to process information received through the visual apparatus based on life experience and distorts reality. For example, he remembers that the snow can only be white, and does not notice its various shades, if not trained. Therefore, the suppression of those colors that do not fit the experience. The camera transmits more real illumination of the subject and its color.
Installation options
A parameter can have several settings:
- Before shooting, when the photographer sets it up
- in the process of color correction, when it is determined whether there are any violations in the white balance, and a decision is made as to whether changes to the color display settings are needed.
Its installation in a modern digital camera can be carried out 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 carry out a white balance correction. Modern devices have a special mode that allows you to change the type of frame lighting. Then the camera corrects for the desired color temperature.
- Some devices may adjust in degrees Kelvin, a unit of measure for color temperature. This helps the photographer a lot in the studio. If you know in advance the color temperature of the lighting fixtures or measure it with a calorimeter, these parameters can be set when setting up the camera.
Features color grading with a gray card
There is also a grayscale color correction mode. This process requires time and negatively affects the speed of shooting. But the result with this method is noticeably better than with the standard camera setup. In this mode, the photographer places a special card with a neutral gray color next to the subject. Before shooting, he calibrates the camera with this card.
Color correction using a sheet of white paper does not give an ideal result, because during the production process special dyes are used to bleach it. In the case of using gray for white balance, it can be guaranteed that this color will be a mixture of pure white and black.
Auto parameter setting
All settings are made when the average frame is neutral in color, and the brightest fragment does not have a neutral white color. 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 this color. Then the picture will look like it was taken not in the light of electric lamps, but in daylight. This algorithm works well in a certain range of color temperature and warm lighting. But if the bright color is not pure white, the image appears distorted in color reproduction.
Colour temperature
It is important to know how the color temperature is arranged in principle, in order to understand what its numerical expression means in kelvins. It describes the light spectrum reflected by a completely black body, depending on what temperature its surface is. This body itself absorbs any incident light, without passing it and not reflecting it. An example of the radiation of this body in everyday life can be a metal or stone, heated to red heat or white heat. Similarly, completely 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, 5,000 Kelvin is neutral, 3,000 Kelvin is the orange, and 9,000 is the blue.
Lighting Features
As the color temperature rises, the color becomes colder, as shorter light waves carry more energy. Daylight or tungsten lamps create light spectra that almost completely correspond to the luminosities of completely black bodies. Other sources, such as fluorescent and most energy-saving lamps, are very different from them. So, the higher the number of Kelvin, 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 photograph.
Setting a parameter in Photoshop for RAW format
Depending on the image format for color correction, it is worth using various tools to make the result better. For example, when dragging a photo in RAW format, a window with the Camera RAW module itself will open in the Photoshop program. Next, you can begin to analyze the image and its settings. To work with white balance, select the options at the top of the settings menu. In the drop-down menu you can find automatic settings, but it is 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 we will deal with the processing features of the JPEG format. Open the image in the program and create a new adjustment layer with curve settings. Go to the channel with the closest hue to what leads to a white imbalance in the photo. We estimate the brightness range of the parasitic hue, for which we find white or black color in the image. If it is in midtones, then we start editing the middle part of the curve. Correction may be required on other channels. You can test yourself using the Eyedropper tool, taking a sample of color from the place that seems the lightest or darkest.