Banknotes of the euro, the currency of the Eurozone, have been in circulation since the first series was issued in 2002. They are issued by the national central banks of the Eurosystem or the European Central Bank. In 1999 the euro was introduced virtually, and in 2002 notes and coins began to circulate. The euro rapidly took over from the former national currencies and slowly expanded around the European Union. Denominations of the notes range from €5 to €500 and, unlike euro coins, the design is identical across the whole of the Eurozone, although they are issued and printed in various member states. The euro banknotes are pure cotton fibre, which improves their durability as well as giving the banknotes a distinctive feel. They measure from 120 by 62 millimetres (4.7 in × 2.4 in) to 160 by 82 millimetres (6.3 in × 3.2 in) and have a variety of colour schemes. The euro notes contain many complex security features such as watermarks, invisible ink, holograms and microprinting that document their authenticity. While euro coins have a national side indicating the country of issue (although not necessarily of minting), euro notes lack this. Instead, this information is shown by the first character of each note's serial number.
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.