What Is Cinema?

Film is silver salt sensitive film, also called film. Made of PC/PP/PET/PVC. Now it generally refers to film, and it can also refer to negative film in printing and plate making. Movies are all black. Generally, there is an English symbol on the corner of the film, which is the film number, indicating which film C, M, Y and K are, and which cmyk (or spot color number) is, indicating what color this film outputs. If not, you can look at the angle of the net to tell what color it is.

Each film (including color film) consists of two basic components: a single or multi-layer latex layer and a film base, which is the support of the latex layer. Emulsion is made of photosensitive particles suspended in gelatin medium. The gelatin on the film is similar to that used in some foods.

The photosensitive substance suspended in gelatin is silver halide particles. This kind of particle is so fine that it can only be observed under a high-power microscope. In the conventional photographic film emulsion of 1 square inch, the content of silver halide crystals is about 40 billion.

Silver halide crystal has the characteristic that its structure will change once exposed to light. The mechanism of this chemical change is not important to us, but the final effect of the change is the most important. How did this change come about? When you shoot, the light shines on the emulsion layer of the film through the lens of the camera. When the light reaches the silver halide crystal, the lump formed by the aggregation of the silver halide crystal is still extremely fine. The amount of light received by the emulsion layer causes the crystal to change and coalesce. That is to say, when light with different intensities irradiates the film, different numbers of crystals in the microscopic field of the film emulsion layer undergo structural changes and coalesce with each other.

Once the film is exposed, it immediately produces a latent image-an invisible image. The film must be developed to turn the latent image into a visible and solid image. When the film is developed, the silver halide crystal whose structure has changed will turn into an aggregate of black metallic silver particles, thus producing a negative image. The non-sensitive crystals on the film, that is, the crystals with no structural changes, are washed away by a chemical called fixing agent, making these parts appear light gray or transparent. The result is that the dark (thick) part of the negative image is the exposed part; The bright (thin) part is the part with less exposure; The completely transparent part is the part that is not irradiated by light. This is the basic process of black-and-white film recording images.

Color film has three emulsion layers, and each emulsion layer also contains different organic compounds that can produce dyes, which are called couplers. They are colorless in themselves, but in the process of color development, they can be coupled with the oxides of color developers to become colored dyes. For negative film, the coupling agent contained in the upper blind emulsion forms yellow, the middle layer forms magenta and the lower layer forms cyan during color development, which is the developed color film. By enlarging or projecting the image on photographic paper or developing the reverse film, the yellow in the upper layer of the film becomes its complementary blue, the middle layer becomes green and the lower layer becomes red, and we get the same color photos or transparent reverse films as the natural state. This is the basic process of recording images with color film.