Moved to Site-19 1993. Origin is as of yet unknown. It is constructed from concrete and rebar with traces of Krylon brand spray paint. SCP-173 is animate and extremely hostile. The object cannot move while within a direct line of sight. Line of sight must not be broken at any time with SCP-173. Personnel assigned to enter container are instructed to alert one another before blinking. Object is reported to attack by snapping the neck at the base of the skull, or by strangulation. In the event of an attack, personnel are to observe Class 4 hazardous object containment procedures. Personnel report sounds of scraping stone originating from within the container when no one is present inside. This is considered normal, and any change in this behaviour should be reported to the acting HMCL supervisor on duty.
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.