Bigfoot is described as a large, hairy, muscular, bipedal ape-like creature, roughly 2–3 metres (6 ft 7 in–9 ft 10 in) covered in hair described as black, dark brown, or dark reddish. Individuals claiming to have seen Bigfoot described large eyes, a pronounced brow ridge, and a large, low-set forehead; the top of the head has been described as rounded and crested, similar to the sagittal crest of the male gorilla, with a strong, unpleasant smell. The enormous footprints for which it is named are claimed to be as large as 24 inches (60 cm) long and 8 inches (20 cm) wide. Some footprint casts have also contained claw marks, making it likely that they came from known animals, such as bears, which have five toes and claws. Proponents claim that Bigfoot is omnivorous and mainly nocturnal.
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.