How Green Screen Worked Before Computers



http://tomscott.com – http://twitter.com/tomscott – For those of us who grew up in the age of CGI, green screen is just “a thing that computers do”. But how did effects like this work before the age of pixels? With the help of some suitably shiny graphics, here’s a quick summary.

Thank you to Matt Gray – http://mattg.co.uk – http://twitter.com/unnamedculprit – for sterling work getting the camera and lighting right!

25 Comments

  • Tom Scott says:

    Sorry this video’s a couple of days late! I’ve been working on BIG EXCITING
    THINGS. (Or at least, I’ve been working on THINGS.)

  • Andrew Joy says:

    Very interesting, would be cool to know whey they switched from blue screen
    to green screen.

  • Dirceu Corsetti says:

    One afternoon? You are getting good man!

  • LiamE69 says:

    Sodium light monochromatic? And there was me thinking sodium was famous for
    its twin spectral lines.

  • Rose Noire says:

    Ahh computers, those magical objects that make jobs obsolete 😛 No wonder
    so many people can’t find work nowadays. I honestly pity the youngest
    generation, many of them will live in poverty. The sad truth is that there
    will always be people too stupid to do an intellectual “futuristic”job. A
    100 years ago they could find a menial job, and live a decent, honest life.
    In 20 or 30 years those jobs will be done by machines operated by
    computers. The poor folks who would gladly do those jobs will be left to
    rot on the streets, or we will have to support more and more people on
    welfare. How long until a revolution?

  • burnzy3210 says:

    But why did we change from blue to green screen?

  • ThePeaceableKingdom says:

    About 2 minutes in he mentions “the BBC used a bit of kit called the
    Quantel Paintbox for Doctor Who as early as 1980”
    Perhaps different kit, but they were greenscreening (CSO) the heck out of
    Doctor Who about a decade before that. See “Terror of the Autons”… also
    “Inferno” I think…

  • Peter Jansen says:

    The history of green screens was good, but come on, you horrendously
    oversimplified how its done today. Yes, it can be done by just chucking in
    a key light node/effect, but that will never be good enough for film level
    stuff.

    Keylight automates a lot of stuff that is usually manually setup and
    meticulously tweaked by experienced artists to get the best matte possible.
    Some processes include despilling the green, preparing the shot before you
    even key with degraining, screen correcting to even out the green on the
    screen, and then you can do the key, which involves a core, edge, and fine
    detail matte, each optimised so you don’t lose any edge detail or have any
    holes in the matte. There are also many different types of keyers;
    lumanince, hue, saturation, whatever.

    Manual roto or paint work may be required to remove unwanted things like
    wires, lights, boom mic or whatever. When compositing the foreground with
    the background, even the background may be treated with an additive key to
    bring back lost hair detail.

    And then you can start to actually integrate the fg with the BG with the
    usual compositing tricks, bloom and lightwrap, grades and colour
    corrections, regrain etc.

    No such thing as perfect key first try ;)

  • DJ Blur says:

    That’s why old movies and music so good because they had to be good actors
    and musicians so they wouldnt waste film and reel to reels and it was
    expensive now hollywood cranks shitty movies and music out left and right
    because all you need is a computer

  • gwaur says:

    Greenscreening with Blender’s video editor is a pain in the ass. They
    should have a real green screen effect strip that’d work similarly to the
    effect seen in the beginning of this video.

  • Sōsuke Aizen says:

    Oh no I found the Eurofags, better leave before the hate comes.

  • BELOWIT MB says:

    You just called yourself a jerk. Hehehe

  • Julian Reischl says:

    You’re right, it is strongly simplified, but informative for inexperienced
    people nonetheless. Very good, then!

  • Scott Manley says:

    This is great. On a similar note you should read about how they restored
    the classic Dr Who series ‘Daemons’. They had an official 16mm monochrome
    film print, and a fan in the US had recorded a colour version on U-Matic
    video tape which was much lower resolution. The restoration team rigged up
    a system where the luminance signal from the film was combined with chroma
    signal from the tape and produced the version we can now watch on DVD. 

  • ROBwithaB says:

    I’m jealous because you got to film this at the YouTube studio. Gonna be a
    while before we get one of those in South Africa…

  • Dale Jackson says:

    I’m not a jerk but I do process chromakey all the time, using a computer
    and After Effects and a special recipe to get the foreground subject off of
    the green background.

  • Klay Anderson says:

    Showing my age here but before you were born, green was Chromakey Blue. 

  • Markus Glanzer says:

    nah, one person with a laptop can do this for free. After effects could be
    considered the (financial) high-end.

  • zerosonico says:

    Someone’s a RHPS fan.

  • Sepehr Nilgoon says:

    از زمانی که دستی در ادیت ویدیو پیدا کردم و توانایی Chroma Key رو فرا گرفتم،
    برام این پرسش بوجود آمده بود که پیش از فراگیر شدن کامپیوتر و در دوران
    فیلمهای آنالوگ این روش ادیت چطور انجام میشده؟ ویدیو پاسخ این پرسش رو میده.

    * کروما کی روشیست که هنرپیشه در جلوی یک پردهء سبز رنگ نقش بازی میکنه و
    هنگام ادیت، هر جا که رنگ سبز وجود داره با تصویر دیگری جایگزین میشه.

    #سینما #هنر

  • BlueComputers says:

    Woah, I learned something today.

    It was greatly presented as well

  • pete burkeet says:

    Couldn’t have green screened your little mic out of the shot there?

  • Robin Powell says:

    I’m more interested in how they do it WITH computers?

  • Charlie Behrens says:

    One of the big problems with less expensive analog video keying gear was
    that it tended to be a bit slow. The result was that it switched from
    background to subject a little bit to the right of where it should have,
    and the same at the other side of the subject. This added a little visible
    edge on the right side of people, especially visible on meteorologists on
    the local tv news.

    Early video artists (e.g. http://en.wikipedia.org/wiki/Nam_June_Paik)
    intentionally amplified this “problem” by looping it through the effect
    repeatedly, to distort images for artistic ideas. For example, a round ball
    would appear to become squashed. It wasn’t very fancy, but it was fun.

  • The Frikanih says:

    Very encouraging. Many times I felt disappointed because of my results with
    chroma or whatever, but after watching this video… hey, my father didn’t
    had this at my age! :D

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