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Comment by hazeii | Hacker News Reader

The effect was actually done using retroreflective tape; the building were indeed a physical model, with the edges covered in 3M Scotchlite tape. From first-hand experience (on other movies) the camera is placed behind a half-silvered mirror placed with a 45 degree tilt, with a projector underneath (in this case shining green light). The net result is the camera and projector are on the same optical axis, so no shadows are visible and because the tape (retro)reflects so strongly that's the only thing that shows up.

We used exactly the same technique on 'Superman', but projecting footage in sync with the camera and the most massive screen of Scotchlite behind the actors (it's must've been something like 200 feet wide and 50 high, so big we had to dig a curved trench several feet deep in the floor of Pinewood's A stage to fit it all in (my boss at the time won an Oscar for the flying FX).

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That’s fascinating. I’m a researcher working closely with today’s Scotchlite technical team at 3M. They recently developed an ambient black looking material that retroreflects: https://www.businesswire.com/news/home/20170502005233/en/3M-...

Let me know if you want a sample :)

That looks like interesting stuff; I was working recently with older 'black' retroreflective materials and the performance wasn't great so we ditched it. I'm in the UK, is it on the market yet or do I need to go through the in-country 3M office?

It is on the market, as C790 Carbon Black. I imagine it is difficult to get small samples as an individual, as 3M typically sells to businesses.

May I ask what you were working with said material for?

Contactless sensing, using retroreflection of a light beam to sense and measure rotation speed. We wanted black so it wouldn't be as visible as the usual silvery-grey, given it was stuck to the sidewall of black tyres.

I keep coming across uses, most recently for tracking research animals in near-darkness (looking down on a floor of scotchlite). The black could be a better choice for that so thanks for the heads-up about it; email me on sfx 'at' tessierlabs.com if you want to know more.

Superman was the last movie my grandfather worked on before he retired. He was with British Lion so probably at Shepperton Studios/Sound City unit, not Pinewood. If you do read this, please send me an email, would be great to see if you ever crossed paths.

Couldn't find your email, but unlikely as I was with the Zoptics unit at Pinewood and we didn't do sound (our gear made a lot of noise!). Spent a lot of my youth around the Chertsey/Staines area though so it's possible. Email sfx at tessierlabs.com if you like, on the offchance.

Note: The "email" field in your profile is private (for password reset and similar stuff). If you want to make it public you must copy it to the "about" field.

Thanks for thw tip!

I'd be interested to know what folks in your field think of the newly developed substance [1]'Vantablack'. Thin carbon tubes that apparently absorb 99.965% of visible light. Are there any cool applications for this stuff in practical effects?

1: https://en.wikipedia.org/wiki/Vantablack

I've been out of SFX for decades so can't speak for current practice; anything really black (classically velvet/black flock) is (was?) useful for hiding all sorts of things from the camera. So I'm just guessing here, but because cameras (more specifically the sensors) are much more limited than the human eye in terms of the range of brightness they can handle it's probably more useful in scientific/direct view applications.

The shadows on the buildings in the article/thread both don't correlate with camera position and change independently.

No need to take my word for it. See "Editing and Special/Visual Effects" by Charlie Keil, Kristen Whissel p. 222:

"One of the more ingenious examples is Escape From New York, which features a wire-frame flight approach display constructed by adding reflective tape to all the building edges of a miniature city model"

It was also covered in Cinefex (must've been sometime in the early 80's if you want to search the back catalogue).

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