Bodybuilding is the use of progressive resistance exercise to control and develop one's musculature. An individual who engages in this activity is referred to as a bodybuilder. In professional bodybuilding, bodybuilders appear in lineups and perform specified poses (and later individual posing routines) for a panel of judges who rank the competitors based on criteria such as symmetry, muscularity, and conditioning. Bodybuilders prepare for competitions through a combination of intentional dehydration, elimination of nonessential body fat, and carbohydrate loading to achieve maximum vascularity, as well as tanning to accentuate muscular definition. Bodybuilders may use anabolic steroids to build muscles. The winner of the annual IFBB Mr. Olympia contest is generally recognized as the world's top male professional bodybuilder. The title was held by Phil Heath, who won every year from 2011 to 2017, but in 2018 the winner was Shawn Rhoden. The winner of the Women's Physique portion of the competition is widely regarded as the world's top female professional bodybuilder.
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.