with more elements result in an image with better resolution but less light per pixel. Thus, like film grain, physical pixel size represents the compromise between resolution and sensitivity. However, while film grains are randomly distributed and have size variation, image sensor cells are of same size and are arranged in a grid, so direct comparison of film and digital resolutions is not straightforward. Instead, the ISO setting on a digital camera controls the gain of the electronic amplifier on the readout circuitry of the chip. Ultimately, high ISO settings on a digital camera operating in low light conditions does result in a noisy image, but the visual appearance is somewhat different from traditional photographic film. The visual and artistic effect of film grain can be simulated in some digital photo manipulation programs by adding grain to a digital image after it is taken. Various raw image processing software packages (such as RawTherapee and DxO PhotoLab) feature "film simulation" effects that apply the characteristics of various film brands, including the graininess. Plugins for the same purpose also exist for various image editors such as Photoshop (e.g. in Nik Collection's Color/Silver Efex). In digital photography, image noise sometimes appears as a "grain-like" effect. Film grain overlay Film grain overlay, sometimes referred to as "FGO", is a process in which film emulsion characteristics are overlaid using different levels of opacity onto a digital file. This process adds film grain characteristics, and in instances with moving images, subtle flicker to the more sterile looking digital medium. As opposed to computer plug-ins, FGO is typically derived from actual film grain samples taken from film, shot against a gray card. Because film grain is difficult to encode because of its random nature, some video codecs, notably AV1, include film grain synthesis, where the film grain is removed during encoding and replaced with parameters that describe the shape and density of the particles, and during playback the decoder uses these parameters to resynthesize the film grain. See also Film speed References Further reading External links Film Grain discussed at FLIP Animation blog Retrieved March 2013 Science of photography