Optical Filter are optical elements that selectively allow light of a certain wavelength to pass through. They are usually made of colored optical or colored chemical films. The Optical Filter has a simple structure and plays a role in passing, limiting and blocking various light. It has a wide range of applications and is widely used in photography creation, printing plate making and scientific photography.

1. Adjust contrast and highlight the subject. In photography practice, color contrast is often used to highlight the subject. For example, when the subject and the background are similar in color and difficult to distinguish, a filter with the same color as the subject is added to make the subject brighter in the photo, so as to achieve the purpose of obvious difference in color between the subject and the background.

2. Adjust the tone and enhance the artistic expression of the picture. The filter can adjust the tone of the photo. By choosing the appropriate filter under certain light, you can shoot the artistic effect you want to express.

3. Adjust the color temperature to suit the color temperature requirements of the photosensitive film. When shooting with color film, especially when shooting with color reversal film, color film has very strict requirements on color temperature. If the color temperature of the shooting scene is inconsistent with the color temperature of the film, the color balance will be destroyed. When the color temperature is high, the photo will be blue, and when the color temperature is low, the photo will be yellow. Therefore, using different Optical Filter under different color temperature conditions (balanced color temperature filters are special Optical Filter) is the guarantee for the color balance of the film in color photography.