How Did They Shoot This?

[Kaylee]

Wooie! More ways to postpone during boring stuff like chores and work ...
thanks Safe-Keeper!

Seriously, that does sound like fun.

 

[MostlyHarmless]

If you watch closely you can see that they are using a dry erase board. If you make a mistake, just stop video, erase and resume where you left off.

 

[gumboot]

Modern compositing has become quite sophisticated. Essentially all you're doing is allocating a particular colour to be "invisible". The familiar "chroma blue" and "chroma green" have been used traditionally but it will work with any colour. The reason those colours have traditionally been used is because they're quite unnatural colours so it's easier to avoid having anything in that shade that you want to keep. Green works better than blue because it's a slightly shorter wavelength (therefore there's less "spill" from the green screen onto your foreground elements and it's easier to maintain lighting separation to avoid those horrible green glow outlines). However if you're shooting natural scenes like, say, a forest, you have to use blue or the trees might disappear too!

These days it goes way beyond mere cycloramas though. Keying can be used on virtually anything you can imagine even individual people or individual limbs. If you've seen "Spartacus: Gods of the Arena" the opening "kill" of episode 1 when a guy gets the top of his head cut off was done by combining one pass of a guy with a greenscreen skull cap and a second of the same performer in a green screen suit save for the top half of his head. (Plus a plate pass as well, of course).

 

[elgarak]

Modern compositing has become quite sophisticated. Essentially all you're doing is allocating a particular colour to be "invisible". The familiar "chroma blue" and "chroma green" have been used traditionally but it will work with any colour. The reason those colours have traditionally been used is because they're quite unnatural colours so it's easier to avoid having anything in that shade that you want to keep. Green works better than blue because it's a slightly shorter wavelength (therefore there's less "spill" from the green screen onto your foreground elements and it's easier to maintain lighting separation to avoid those horrible green glow outlines). However if you're shooting natural scenes like, say, a forest, you have to use blue or the trees might disappear too!

These days it goes way beyond mere cycloramas though. Keying can be used on virtually anything you can imagine even individual people or individual limbs. If you've seen "Spartacus: Gods of the Arena" the opening "kill" of episode 1 when a guy gets the top of his head cut off was done by combining one pass of a guy with a greenscreen skull cap and a second of the same performer in a green screen suit save for the top half of his head. (Plus a plate pass as well, of course).

Blue screen was used for analog optical processes, as blue has the higher energy/shortest wavelength, and you could simply use an optical filter that cut off all shorter wavelengths. In fact, in the optical days, often the chroma keying was done with UV light and fluorescent background. Was used to good effect in Star Trek TNG (with a fluorescent background that looked bright orange in the visual range) since it cut down on time and thus, money. With the switch to digital, it was found that green works easier, because the digital filters were a lot more narrow than the old analog filters (the color to cut out did not need to be at end of the spectrum, or even outside, as UV), and green was chosen because of sensitivity of the sensors and high brightness in most lights' spectra (such as sunlight). Bright green is also a lot less like likely to show up in foreground features you do not want to remove (clothing and eye color, for instance). But generally, nowadays you can use any color, or none at all. It's just a (lot, lot, lot) more work with unprepared footage without a monochromatic background.

 

[bottsranzee]

No question, it is a cat playing with itself in a mirror that has been altered.