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Author
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Topic: Blue screening in black&white???
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mxpx_99
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posted 03-26-2000 09:29 PM
how did they ever do blue screening in black and white films???i wonder this cuz it seems like there are only so many shades of colors in black and white film so how would they ever successfully key out a single color? i was just wondering...
later |
Ghent_ep
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posted 03-26-2000 09:59 PM
Wasn't blue screens back then. Usually film matting where they actually cover a section of the view for the lense in which they wanted to insert the new image/footage. Those areas would not get exposed to light (like a section of film that could literally still be used to replace with anything else) on the reels of film. Then they would back the film to the start and film the scene or image that would take the place of the black areas. Wallah, early keying. It was used extensively to create large open environments like the Wizard of Oz and Gone with the wind, They'd replace the blank sections with matt paintings of bigger environments, or simple environments that never existed. It's actually still being used in a few recent films. The Adams family and Dennis the Menace (5 or so years back) used the matting process for their skys etc regularly. Kind of weird though because both had alot of blue screen work to. The reason I believe is because the Matt Painter actually used the piece of film of the shot he was to pain the matt around as the outline which he painted around. But no reason that couldn't have been done in CG or blue screen either. So who knows. Might just have been ignorent film makers a little behind on technology =)------------------
Ghent
Endor Productions, Inc. [This message has been edited by Ghent_ep (edited 03-26-2000).] |
RipSUp
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posted 03-27-2000 01:25 AM
I went to Universal Studios last week and they used blue screening to redo the scene from vertigo in Black and white. They said it was how thye did it back then. |
Ghent_ep
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posted 03-27-2000 10:37 AM
If they redid it, it was recently, back then they didn't have that ability. And Universal studios is a theme park, not a film house, the people who work there aren't of any authority. They're just normal people trained to do their job often times there. There was no such thing as keying in the early days. Compositing and keying was actually brought fully into the industry by George Lucas when he created ILM for a New Hope. The machine they devised to do the job was really the first of it's kind to allow keying services. There had been previous attempts but nothing this solid. Generally effects were generated with matting or rear-screen projection before that time.------------------
Ghent
Endor Productions, Inc. |
Mister Twisted
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posted 03-27-2000 01:59 PM
Blue screen compositing was around for decades before "Star Wars". There's actually an apocryphal story that green was first used instead of blue because the blue was too close to the colour of Paul Newman's eyes.Pre-computer compositing usually involved running several strips of film through the gate simultaneously. Off the top of my head, I can't think of a specific B&W movie that I know for certain uses blue screen, but here's how it would be done: Film the foreground element in front of a blue screen. In the camera is film that will be developed normally, on top of some blue leader, on top of another piece of film that will be timed in the lab so that (if it's reversal film) the blue areas are completely opaque while the rest of the film is transparent (the blue leader only allows blue light through to the film). Now you take a negative of the rear piece of film, and film your background with the negative you just made (the matte) in the camera in front of the film that you're going to develop normally. Now rewind the film, and replace the matte with the film that you shot of the foreground and the original matte that you made the negative from. Now expose the film again (either in an Optical Printer, or just by aiming the camera at an even white light source) and you have your composite. This sounds like a lot of trouble, and it is - that's the reason optical effects were so expensive. In one way, it's easier to do blue screen with monochrome film, because you don't have to worry so much about colour matching, but it still suffers from several problems that can't really be eliminated entirely: Firstly, when film is processed, it'll warp and shrink slightly, by an unpredictable amount. That's the reason that you'll see matte outlines on so many old films. Secondly, if you want to have a lot of effects composited together, there's a limit to how many matte layers you can run through the gate at one time (and as I've already mentioned, you can't just solve this problem by cumulatively pre-comping the mattes, even if you could afford to, because the shrinking effects would multiply). and THAT'S where "Star Wars" comes in. The principal innovation that Lucas's effects company (which I believe was called "Apogee" at the time, I think "Industrial Light and Magic" came later,) made use of was John Dykstra's "Dykstraflex" motion-control camera. If you can repeat exactly the same camera move over and over, you can make a much better composite. First you film your foreground model, unlit, against the bluescreen for your matte pass. Now you take the matte film out of the camera, and turn the blue screen off, light your model the way you want it to look and film it again. Because there's no blue spill, and there's nothing in front of the film to degrade the image quality, you get a much better composite. The only things they couldn't improve were bluescreen shots with actors (because you can't get motion-control actors) and the shrinkage artifacts, which was the main "artistic" (as opposed to the obvious "money-spinning") reason for the CGI special editions. Incidentally, "Vertigo" (which did, by the way, use several blue screen mattes, and in one instance, quite strangely; rather than compositing the two together, the two parts are played consecutively) was in colour... |
Ghent_ep
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posted 03-27-2000 02:22 PM
Hmm, didn't know that. Actually never even heard of such a thing. Everything I've always read or seen mentioned matting being the only compositing option for the years of black and white. And that the Matting was generally done with solid black or dark colors which would be unexposed, then backed and replaced later with the new image. Blue or white colors would be exposed during the filming. The running of multiple strips of film seems much later on technology wise so I'd like to get a date from you if I can when you believe that method was begun.[This message has been edited by Ghent_ep (edited 03-27-2000).] |
Prism
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posted 03-27-2000 02:36 PM
Ever notice in the Superman movies, how Superman's outfit is sorta greenish in the scenes where he's flying? I figure that must be because they filmed him against a blue screen, and obviously they couldn't have his outfit the same color. It doesn't look too good.. seems like they could've thought of something better.Isaiah |
Reg Spoon
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posted 03-27-2000 03:57 PM
Ghent_ep, the original King Kong (1933) featured a number of shots with the Dunning process, an early form of bluescreen. In fact I think they used a red screen.That's 40 plus years before Star Wars. Not all FX were invented in 1977. |
Reg Spoon
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posted 03-27-2000 04:10 PM
Forgot to mention the Dunning process required you to bi pack several pieces of film in the camera when shooting. There was also another process named the Williams process. As this was the early 1930's, both processes worked with B&W film. Hope this helps Ghent_ep. |
Ghent_ep
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posted 03-27-2000 05:13 PM
heh, I was only saying I thought that was the first time real keying was done with their compositing system. I never implied anything else about ILM or a New Hope. And the articles I have read on Ray Harrihausen (Spelling) and many other legends of compositing generally referred to their work as matting on dark backgrounds or litterally removing sections by hand then hand rolling in the new footage. My impression was that other forms of compositing were used only by a few film makers. And much of King Kong was done with matting as well. Infact I suppose the method you describe could be called matting as well because it involved actually Laying another piece of film or filming ontop of an undevelopped portion of a film. Matting is simply referred to as physically and I guess in your case optically placing one image on another. Where keying you actually replace the original segments later on. I don't know maybe we just got a misunderstanding, still seems really different from what I've always read in stop motion based films etc.------------------
Ghent
Endor Productions, Inc. |
EricM
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posted 03-27-2000 08:11 PM
Ghent_ep, the matte process you talk about has been around for a long time. The Great Train Robbery used it in several shots. This is still a good way to do simple composites today, becasue it can be done on the original camera neg. Even digital effects have a bit of a generation loss when they go back to film.
Oh, and just to split hairs: the process of putting one image on top of another is called compositing, not matting.
Blue screen has been around for a long time. What Mister Twisted said is true (except that ILM was always called ILM. After Star Wars, John Dykstra started his own company called Apogee, which has since gone out of business).
Matting is kind of a genaric term. Any method that leaves a section of film unexposed so that antother image can be placed there is a matte (not to be confused with a matte painting, which is often matted into some other footage).
The matte created by blue/green screening of live actors used to be called a traveling matte, because it changed shape over time.
Most of Harryhousen's work, and the work in King Kong was done with rear screen projection (and so was Robocop). Not to say there was no matting at all.
I have also heard of a system used in the B&W days called sodium screen. I don't know it there was sodium on the screen or in the lights, but it made a bright yellow colour. Anyone else hear of this? I forget where I got this from.[This message has been edited by EricM (edited 03-27-2000).] |
Critter
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posted 03-27-2000 09:10 PM
Here is a short history and technology lesson. Blue screening has been around since at least the twenty's. Real time has been fairly recent. The reason for the use of the c0olor blue is very easy. There is a specific color of blue that is invisible to black and white film. Is is called non-repro blue. You can buy pencils with this color. The non-repro blue color is also invisible to photocopiers. The first blue screening used a non-repro blue back ground. This left that part of the film clear. When duped to high contrast film, you would get a black siloett of the object in front of the blue screen. This was then dupped to reversal film, giving a negative of the siloett. These are the four pieces of film used to rotoscope the bluescreening into one piece of film. The siloett was laid over the master background. This was exposed so that the area covered by the siloett was a 'hole' in the new film. Next, the outline was added to the bluescreen film, and this was exposed on the film. This filled in the'hole on the final film. The four layers of film are reeled up onto seperat reels, and the new film is developed. Now, if you think about one of these layers being off by 1/10,000 of an ince, and the clear lines it would leave in the film, you will understand why it was not done often. Besides the cost of all that film, and time to do the shot. Once a machine was developed that could actually do it all at once automaticly (rotoscopeing), it was used more often. Back in the thirties, it was done two layers at a time.------------------
Rex Winfrey
Critter Creation Shop
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mxpx_99
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posted 03-27-2000 09:20 PM
woah cool...i didnt know that |
Ghent_ep
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posted 03-27-2000 09:42 PM
Well I'll be a monkey's uncle. There's always a new thing to learn everyday I guess. Thanks for info guys.------------------
Ghent
Endor Productions, Inc. |
ebrigman
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posted 03-28-2000 09:18 AM
the sodium process used sodium vapor lights and a yellowish screen... If you wnat to see info on this read "The technique of Special Effects cinematography" by Raymond Fielding... amazing book... | |
