Static electricity

I remember having to do all the flying weaponry on the afore mentioned shot animated by Roy and Raymond, a scene that ended up being nicknamed: Starwars, due to it's plethora of flying objects.
It's funny now, remembering the lengths I went to, to make sure things didn't look repetitive or predictable. Seeing the finished item, it zips past you at such a clip, that even I hardly see any of the stuff I animated into it.
I guess it's what I now refer to as the Maple syrup concept.
You have to distil a lot of maple sap into a thimble full of syrup but only the concentration of vast amounts of input into a tiny amount of output will make it taste as sweet as it ultimately does.
The 18 foot long background for this shot hat to be stuck with sellotape to the walls of the camera room, and unstuck and held by assistants for the motorized move between frames and then restuck to the walls.
I remember John explaining the process of 8 or ten camera passes on this monster of a scene.
Needless to say, that meant that the film in the camera had to be rewound those 8 or ten times to be re-exposed again and again.
After almost a week of shooting the shot finally turned up in the moviola and lo and behold, Dick spotted something...
The film, passing through the felt lined slots in the reel housing, had built up enough static electricity to start sparking inside the camera, and those sparks were visible as thin blue lightning on the exposed film.
Luckily, Dick deemed it mild enough a fault, not to warrant a reshoot, which probably saved John and Grahams life...

And here is the proof...

Guest blogger Brian Riley:

This just came in from cameraman Brian Riley. I thought I'll post it right away as it responds to Michael's post. I hope Don Hertzfeld will come across this blog one day as he is one of the few animators I know of who still use real film.
Now, Brian Riley:

“Bumped into Paul Dilworth (literally) on the football pitch last week and he told me to check out your 'Thief Blog'. Nice job. As you know I spent 2 years in the camera room and it was an experience I wouldn't have missed for the world, bizarre as it was at times.

I don't know what prompted the explanation of the 'bipac' (I'd have spelled it 'bi-pack', but to be honest I've no idea what is the accepted spelling) but I can confirm that that was pretty much the process used on many shots, the memory of which I've suppressed to save myself the pain of re-living the endless re-shoots that some of these scenes necessarily required, rarely for operator errors it has to be said in the camera room's defense - more often for some perceived artistic imperfection. Normally I had no problem doing re-shoots on the Thief - it was completely Dick's film and in my eyes he had an absolute right to have it exactly how he wanted it and I always saw it as a bit of privilege to work on it anyway. However the bi-pack scenes were such buggers to get right from a technical standpoint it was a little frustrating at times to have to re-do them. From what I can remember, we cheated the process slightly by not running the high contrast negative through in a bi-pack when we shot the animation top lit on colour stock, possibly for reasons of time and convenience - remember we only had 2 cameras and we were often running them 24 hours a day in 3 x 8 hour shifts.

After we shot the high contrast footage, we off-loaded it and sent it off for processing then we loaded up colour stock and simply put the animation on a top-lit (pristine) black bg on the table. Arguably it would've been better to use the neg in a bi-pack but I don't think we did. Not using the neg meant we could get on and immediately shoot the colour animation and once that was done the camera would be freed up - it was obviously crucial that the camera and table etc was in exactly the same position for shooting the matte and colour versions of the animation. Although in theory with a computer controlling all the axes we could precisely duplicate positions, in practice the physical nature of the mechanics, cog wheels, worm drives, shafts, bearings etc meant there was always an infinitesimal amount of slack that could mean the difference between getting it right and seeing a matte line. So we always shot the colour character run immediately after shooting the mattes. Once we'd made the high contrast matte and got it back from labs, we used the positive (printed on neg perf stock) in the bi-pack with the raw colour stock with the character exposed on it, while we did the camera movement on the bg, exactly as described in the blog. Also vital was that the processed matte stock and the raw colour stock were synchronised for every run - we shot a cross at the start of the matte run and then had a set number of frames of clearance, slate etc we would run before shooting frame number 1 of the animation. The raw colour stock would be physically marked in the gate (usually with a good old indelible Sharpie) at the exact point when the film was down on the registration pins and the shutter would be open. These marks would be carefully aligned every time we ran the matte and colour stock together in the bi-pack.

Off the top of my head one scene that we did this with was 'The Balls Have Gone!' shot when the old king peers out through the window and then goes running about in a panic, while we pull back from his open mouth all the way to a 'God's Eye View' of the city using multiple takeovers on both animation and bg - another whole kettle of fish in itself, matching the speed and movement and so on.
(This scene was called Mouth to Mountain, see post from Jan.16)

I read a couple of the December 2007 bits. Thanks for the name check by the way. You were right to quote John's reminder to you regarding the tightrope we walked every day in the camera room. In those pre-digital, pre-render preview days it was in the nature of the cameraman's job that you had to be right every frame; one slip-up, one lapse of concentration, could often result in having to go right back to the beginning and mean hours or even days of lost work.

Sometimes shooting on 35mm, which is relatively easy to cut, you could put in a few blank cut-out frames, whiting out the error, then pick up where you left off. On the Thief though there was no such luxury or leeway, with virtually every scene having multiple exposures, so that characters, props, bg's etc could all be isolated and lit separately (much as they would on a live action set) it was impossible to do any sort of a cut back, except on the very first exposure and then you wouldn't do it, because you would have to remember that cut-back for every subsequent exposure and adjust your frame count accordingly, thus creating one more parameter to concentrate on.

On bi-pack scenes of course it was simply impossible to repair an error. One camera mistake was one too many and that was that - everything was in the bin, matte roll included. It all had to be done again. And Dick being a chap that was not particularly forgiving as to human frailty when it manifested itself in cock-ups on his film, meant that we were daily under as great a pressure as I've experienced on any film anywhere. But I think I can speak for all us when I say that it was still an exciting and inspiring situation to be in.

You were also right to underline the ground-breaking work John did in and under the camera and that us camera guys carried out under his supervision, we also contributed a bit of our own inspiraton here and there - but 99% of it was down to John interpreting Dick and Roy's artistic vision and putting it onto the screen using any number of innovative techniques as well as few 'old school' dodges that John had learned over the years.
All the above is dragged up out of my scarred and fading memory. I do get the odd message from Johnny Leathertrousers and I generally see him for a pint every time I'm in London so I'll send out the carrier pigeon and see if I can make contact - he obviously would be the man to speak to confirm my recollection. Though he's even more senile than me so don't bank on it!”

Bipac

The word Camera bipac has been used several times in previous posts, and I'm not quite sure if the technique used in these cases was actually a bipac.
No way of telling now, without talking to Mr. Leatherbarrow, but a nice opportunity to explain the system to you who are probably all used to the limitless possibility of digital compositing.
The problem with double exposures in a rostrum camera is, that for every run of animation, you need a run of mattes to cut a piece of the background out, that you want to expose the animation into.
As the mattes are produced from the same artwork as the cels, it is impossible to perform any zoom into or out of the background without also performing that zoom on the character and it's mattes.
Let's say you want the camera to travel backwards with the character, walking towards camera and the Background receding, you would have to animate the character getting bigger throughout the scene.
On slow moves, xeroxing the artwork up incrementally ultimately stumbles across the problem that photocopiers can go no less than 1% at a time, too coarse for subtle size increases.
So some clever person invented the bipac.
And here is how it works:

The cels, back painted for opacity, are shot on a light box at the same size, that the animation is supposed to appear in the shot.
The film stock used is high contrast black and white stock, so that when the stuff comes back from the lab, we have a black on white animation positive and a white on black animation negative.

















Now comes the clever bit.
Let's say we want the character to remain at a constant size in the shot, while the background recedes into the distance.

A fresh piece of film is put into the camera, with the previously filmed animation negative sandwiched below it, cutting out part of the light that comes through the lens.
The cels are now placed onto a coloured card that resembles the characters outline colour and synched up with the sandwiched film inside the camera.
The animation is shot frame by frame.

















The result is exposed animation on film, surrounded by unexposed film emulsion.
The animation negative is now removed from the camera and replaced by the previously shot animation positive.
That positive now covers neatly the previously shot character cel animation, but leaves exposed the previously unexposed surrounding area.
As all the matting takes place inside the camera, we can now proceed to zoom into or out of the background at will, double exposing the receeding Background behind the static character.

















This technique was used to double up the roller coaster move inside the war machine at a reduced size in the background while using the original run of the animation as it's own matte.











Clever hey?