Film grain is an optical effect that resembles a vast field of tiny particles in images developed from celluloid film. Film captures images via an emulsion of light-sensitive silver halide crystals, and these particles create a grainy visual texture. Since motion pictures run at 24 frames per second and no two frames have the same arrangement of grains, the movement of 35mm film frames creates a shifting granular texture that gives the image a certain aesthetic quality. Today, most movies are shot on digital cameras, so graininess is no longer a ubiquitous feature in cinema. Filmmakers can simulate the look of film grain using editing software without shooting on photochemical film. The terms “film grain” and “digital noise” are sometimes used interchangeably, but these similar-looking effects are not the same. In the early days of digital cinematography, image sensors’ lower resolution and light sensitivity meant that some of the pictures contained digital noise. Rather than actual silver halide crystals, digital noise represents incomplete digital information in the form of pixels. Digital noise happens much less today, as digital sensors have become much more sensitive. Celluloid film is analog technology, so film grain is organic and impossible to calibrate perfectly. There are many variables that can cause film grain: 1. __Exposure__: Both significant under-and over-exposure will increase the graininess of your film. Usually, underexposure, which happens when you take photos without enough light, is more likely to bring out the grain. Still, overexposure will cause a similar effect, especially in highlights and midtones. 2. __Development time__: In photochemical film processing, leaving the film in the developing solution for longer than the standard amount of time—called “pushing” the exposure—will also increase the grainy look of the finished product. 3. __ISO setting__: The ISO setting, also known as the film speed, refers to the film stock’s light sensitivity, indicated by a number. Film companies like Kodak offered a range of options: higher ISO film (also known as “faster”) is more sensitive to light, but has larger and more noticeable grain, while low-ISO film is much clearer, and the grain is less visible. In the era of digital image capture, film grain is no longer a physical component of the image itself, but it is a stylistic choice. Grain gives the image a “film look,” which contrasts with the ultra-crisp and clear images that high-resolution digital cameras produce. You can create the effect of film grain using post-production software, digital photography software, or film overlays: 1. __Post-production software__: Raw footage almost always undergoes various modifications and can be color-corrected and manipulated on set to give the director and cinematographer a preview of the finished product. In the [editing suite](https://www.masterclass.com/articles/guide-to-film-and-video-editing), Adobe After Effects and Adobe Premiere typically feature plugins that add film grain to the image. Editors can calibrate grain size, structure, and texture to achieve the desired effect. 2. __Noise filter__: Digital photography software like Photoshop usually includes a noise filter, which you can shift up and down to add more or less of the film grain effect to still photos. 3. __Film grain overlay__: In cinema editing, it is usually necessary to download a film grain overlay to create the effect. Download an overlay plugin to add to your editing software and use it in conjunction with a blend mode to create the effect. Some filmmakers prefer the clarity of digital video, others the softness and texture that grain can impart. Very grainy images might affect a mood of gritty realism, whereas fine-grain texture can help soften contrasting areas of light and darkness, even creating a subtle glowing effect. This can establish a nostalgic or dreamy quality to the experience. Become a better filmmaker with the [MasterClass Annual Membership](https://www.masterclass.com). Gain access to exclusive video lessons taught by the world’s best, including James Cameron, Spike Lee, David Lynch, Shonda Rhimes, Jodie Foster, Martin Scorsese, and more. Film grain refers to a textural component of photochemical film that can be recreated as an aesthetic for digital images.