Mysticism is the practice of religious ecstasies (religious experiences during alternate states of consciousness), together with whatever ideologies, ethics, rites, myths, legends, and magic may be related to them. It may also refer to the attainment of insight in ultimate or hidden truths, and to human transformation supported by various practices and experiences. The term "mysticism" has Ancient Greek origins with various historically determined meanings. Derived from the Greek word μύω múō, meaning "to close" or "to conceal", mysticism referred to the biblical, liturgical, spiritual, and contemplative dimensions of early and medieval Christianity. During the early modern period, the definition of mysticism grew to include a broad range of beliefs and ideologies related to "extraordinary experiences and states of mind."
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.