Chroma key compositing, or chroma keying, is a visual-effects and post-production technique for compositing (layering) two or more images or video streams together based on colour hues. The technique has been used in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture, and video game industries. A colour range in the foreground footage is made transparent, allowing separately filmed background footage or a static image to be inserted into the scene. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as colour keying, colour-separation overlay, or by various terms for specific colour-related variants such as green screen or blue screen; chroma keying can be done with backgrounds of any colour that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most distinctly in hue from any human skin colour. No part of the subject being filmed or photographed may duplicate the colour used as the backing, or the part may be erroneously identified as part of the backing.
Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that direct or indirect sunlight can provide effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Energy savings can be achieved from the reduced use of artificial (electric) lighting or from passive solar heating. Artificial lighting energy use can be reduced by simply installing fewer electric lights where daylight is present or by automatically dimming or switching off electric lights in response to the presence of daylight – a process known as daylight harvesting.
Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Daylighting is sometimes used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings. Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants.
Cinematography is the art of motion picture photography.
Low-key lighting is a style of lighting for photography, film or television. It is a necessary element in creating a chiaroscuro effect. Traditional photographic lighting uses a key light, a fill light and a back light for illumination. Low-key lighting often uses only a key light, optionally controlled with a fill light or a simple reflector.
Day for night is a set of cinematic techniques used to simulate a night scene while filming in daylight. It is often employed when it is too difficult or expensive to actually shoot during nighttime. Because both film stocks and digital image sensors lack the sensitivity of the human eye in low light conditions, night scenes recorded in natural light, with or without moonlight, may be underexposed to the point where little or nothing is visible. This problem can be avoided by using daylight to substitute for darkness. When shooting day for night, the scene is typically underexposed in-camera or darkened during post-production, with a blue tint added. Additional effects are often used to heighten the impression of night.
Three-point lighting is a standard method used in visual media such as theatre, video, film, still photography, computer-generated imagery and 3D computer graphics. By using three separate positions, the photographer can illuminate the shot's subject however desired, while also controlling the shading and shadows produced by direct lighting.
Fill flash is a photographic technique used to brighten deep shadow areas, typically outdoors on sunny days, though the technique is useful any time the background is significantly brighter than the subject of the photograph, particularly in backlit subjects. To use fill flash, the aperture and shutter speed are adjusted to correctly expose the background, and the flash is fired to lighten the foreground.
High-key lighting is a style of lighting for film, television, or photography that aims to reduce the lighting ratio present in the scene. This was originally done partly for technological reasons, since early film and television did not deal well with high contrast ratios, but now is used to suggest an upbeat mood. It is often used in works of comedy. High-key lighting is usually quite homogeneous and free from dark shadows. The terminology comes from the higher balance in the ratio between the key light and the fill light in a traditional three-point lighting setup.
In television, film, stage, or photographic lighting, a fill light may be used to reduce the contrast of a scene to match the dynamic range of the recording media and record the same amount of detail typically seen by eye in average lighting and considered normal. From that baseline of normality, using more or less fill will make shadows seem lighter or darker than normal, which will cause the viewer to react differently, by inferring both environmental and mood clues from the tone of the shadows.
This article contains a list of cinematic techniques that are divided into categories and briefly described.
Rembrandt lighting is a standard lighting technique that is used in studio portrait photography and cinematography; it is also used in contrast with butterfly lighting It can be achieved using one light and a reflector, or two lights, and is popular because it is capable of producing images which appear both natural and compelling with a minimum of equipment. Rembrandt lighting is characterized by an illuminated triangle under the eye of the subject on the less illuminated side of the face. It is named for the Dutch painter Rembrandt, who occasionally used this type of lighting.
Hard and soft light are different types of lighting that are commonly used in photography and filmmaking. Soft light is light that tends to "wrap" around objects, projecting diffused shadows with soft edges, whereas hard light is more focused and produces harsher shadows.
In lighting design, backlighting is the process of illuminating the subject from the back. In other words, the lighting instrument and the viewer face each other, with the subject in between. This creates a glowing effect on the edges of the subject, while other areas are darker. The backlight can be a natural or artificial source of light. When artificial, the back light is usually placed directly behind the subject in a 4-point lighting setup. A back light, which lights foreground elements from the rear, is not to be confused with a background light, which lights background elements.
Portrait photography, or portraiture, is a type of photography aimed toward capturing the personality of a person or group of people by using effective lighting, backdrops, and poses. A portrait photograph may be artistic or clinical. Frequently, portraits are commissioned for special occasions, such as weddings, school events, or commercial purposes. Portraits can serve many purposes, ranging from usage on a personal web site to display in the lobby of a business.
In photography and cinematography, available light refers to any available source of light that is not explicitly supplied by the photographer for the purpose of taking pictures. The term usually refers to light sources in the surrounding environment that are present naturally or artificial lighting that are already pre-existing. It generally excludes flashes, although arguably flash lighting provided by other photographers shooting simultaneously in the same space could be considered available light. Light sources that affect the scene and are included in the actual frame are called practical light sources, or simply practicals.
In photography and cinematography, a reflector is an improvised or specialised reflective surface used to redirect light towards a given subject or scene.
Photographic lighting refers to how a light source, artificial or natural, illuminates the scene or subject that is photographed. Photographers can manipulate the positioning and the quality of a light source to create visual effects, potentially changing aspects of the photograph such as clarity, tone and saturation to create an accurate rendition of the scene.
Low-key photography is a genre of photography consisting of shooting dark-colored scenes by lowering or dimming the "key" or front light illuminating the scene, and emphasizing natural or artificial light only on specific areas in the frame. This photographic style is usually used to create a mysterious atmosphere, that only suggests various shapes, often graphic, letting the viewer experience the photograph through subjective interpretation and often implies painting objects or the human body with black non-toxic dyes or pigments.
A light tent, a kind of photography light modifier, is a box used for taking photos of objects without casting shadows. It can, for example, be used to take pictures of a physical product for use in an encyclopedia, for documentation or for marketing. The combination of evenly distributed lighting and the diffusing material means that minimal shadows are cast, and it can appear as if the pictured product is "floating in nothing", and a neutral image without a disturbing background can be achieved. Glossy or reflective objects in particular can require a light tent in order to avoid unwanted reflections in the picture.
