blue screen
Blue screen (noun) means a blue backdrop used in film and TV production for chroma-key compositing — historically the original chroma-key colour before green became the broadcast standard. Example: “Early effects-heavy films relied on a blue screen to composite actors into digitally created skies.”
Fill the gap
Can you complete this real example?
Early effects-heavy films relied on a _____ to composite actors into digitally created skies.
Etymology
A compound of blue + screen, from the historical film-making technique of using blue backgrounds.