A coffin is a funerary box used for viewing or keeping a corpse, either for burial or cremation. The word took two different paths. Old French cofin, originally meaning basket, became coffin in English; its modern French form, couffin, means cradle. A distinction is often made between coffin and casket: the latter is generally understood to denote a four-sided or eight-sided (almost always a rectangular or long octagonal) funerary box, while a coffin is usually six-sided or twelve-sided (almost always an elongated hexagonal or elongated dodecagonal) funerary box. However, coffins having a one-piece side with a curve at the shoulder instead of a join are more commonly used in the United Kingdom (UK).
Chroma key compositing, or chroma keying, is a special effects / post-production technique for compositing (layering) two images or video streams together based on color hues (chroma range). The technique has been used heavily in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture and videogame industries. A color 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 color keying, colour-separation overlay (CSO; primarily by the BBC), or by various terms for specific color-related variants such as green screen, and blue screen – chroma keying can be done with backgrounds of any color that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most distinctly in hue from most human skin colors. No part of the subject being filmed or photographed may duplicate the color used as the backing.