For the green screen effect, studios could actually use specialized optical filters. They could apply one filter that would ignore a specific wavelength of the color green. Then they could film ...

The result was what eventually became the basis of the modern green screen ... Unlike the blue screen, which required tampering with actual film strips to achieve the effect, Vlahos' method ...

Head over to the website where you’ll be prompted to select the color blue or green (whichever you think the shade looks like ...