# How do they do this special effect? **URL:** \ **Category:** Cafe Society\ **Created:** [July 20, 2003, 3:41am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695 "2003-07-20T03:41:09Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Trigonal\_Planar](https://avatars.discourse-cdn.com/v4/letter/t/0ea827/32.png) [@Trigonal\_Planar](https://boards.straightdope.com/u/Trigonal_Planar)\ **Post date:** [July 20, 2003, 3:41am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/1 "2003-07-20T03:41:09Z")
Everything in a scene is in black and white except for one person. And this person “fully interacts” with the scene, so its not just something they layered on top. ---
**Author:** ![Wumpus](https://avatars.discourse-cdn.com/v4/letter/w/8c91f0/32.png) [@Wumpus](https://boards.straightdope.com/u/Wumpus)\ **Post date:** [July 20, 2003, 4:03am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/2 "2003-07-20T04:03:00Z")
Nowadays, it’s quite simple … they put the scene on a computer, then they digitally remove the color from everything in the frame but the one person. Then they transfer the scene back to film. You can use the same technique to make all sorts of subtle color changes–e.g. make the grass more green, make the background darker, etc. If you want to know more about digital color correction (geez, I sound like someone on an after-school special), there are features about it on the Se7ven, Fellowship of the Rings: Extended Edition, and O Brother Where Art Thou DVDs. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [July 20, 2003, 5:18am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/3 "2003-07-20T05:18:11Z")
Since you pretty answered the question, I’ll see if I can keep this party going with some more SFX questions: 1. How do they “enhance” old movies? You know where they clean up a movie from the 80s or earlier? How can they make the picture clearer then the limitations of the original film. ---
**Author:** ![Zenster](https://avatars.discourse-cdn.com/v4/letter/z/cdc98d/32.png) [@Zenster](https://boards.straightdope.com/u/Zenster)\ **Post date:** [July 20, 2003, 6:06am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/4 "2003-07-20T06:06:15Z")
First question: Image subtraction with post process color elimination from background. They identify the one image component that the computer is supposed to leave with full coloration (usually via outline plotting). The system subtracts this from the overall picture, eliminates all color from the remaining frame and leaves the outlined object unretouched when they are reintegrated. Second question: Noise reduction via computerized image activity analysis. The processor looks for minor image features that last for only one or two frames or do not have a correct movement profile compared to other background or foreground components. ---
**Author:** ![Walloon](https://avatars.discourse-cdn.com/v4/letter/w/fbc32d/32.png) [@Walloon](https://boards.straightdope.com/u/Walloon)\ **Post date:** [July 20, 2003, 6:28am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/5 "2003-07-20T06:28:04Z")
I’m a little troubled that you think that movies from the _1980s_ are creaky and need cleaning up. Anyway . . . There are several different methods used in film restoration. The first is to look anywhere and everywhere for the original film elements — the camera negative for the picture, and the separation tracks (dialogue, sound effects, music) for the sound. If those are not available, then you look for a fine grain interpositive (made from the camera negative), or an internegative (made from the interpositive). Sometimes the original film elements are incomplete (many times the negative was cut when the film was reissued at a shorter length), and so the segments missing from the original film elements must be replaced with sections from old prints. Next, you physically clean the film elements by hand and repair any bad splices or broken sprocket holes. Then comes the conversion of each frame to a digital image with a high resolution film scanner working at 30 seconds per image (or 1,200 hours for a 100-minute feature). The storage size of a digital color image is up to 45 MB per frame. Once the digital conversion is done, flaws in individual frames can be corrected by digitally copying and pasting a similar section of the image from an adjacent frame. [Restoring _Gone With the Wind_](http://movieweb.com/movie/gonewind/press2.html) [Restoration of _My Fair Lady_](http://www.in70mm.com/newsletter/1995/38/mfl/mfl.htm) [Restoring _Rear Window_](http://www.cnn.com/SHOWBIZ/9712/11/rearwindow.restoration.lat/) ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [July 20, 2003, 7:31am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/6 "2003-07-20T07:31:29Z")
If you would like to see a demonstration of this technique, get the _Pleasantville_ DVD and check out the “behind the scenes” special features. If you recall, the film is about two modern-day kids who get magically inserted into a black-and-white television program set in an impossibly idyllic town. The presence of the kids exposes some of the hypocrisies of the idealized world, and gradually transforms the town’s social structure. The transformation manifests visually as black-and-white changing to color. Sometimes it’s objects; sometimes it’s locations; most commonly it’s people. Anyway, the point is, the whole movie was shot on color film, and then transferred to computer, whereon the color was removed as desired. For the early all-B&W scenes, all of the color was removed. For the later scenes, color was removed from everything _except_ the item(s) that had changed. There’s a weird little side note about how this technique was used: In one scene, the Joan Allen character has turned color, but she is ashamed, and she hides it with B&W makeup. The Tobey Maguire character realizes this, and wipes the makeup off her cheek, exposing the skin tone. Except, of course, that if you think about it, there wasn’t any B&W makeup to rub off; she was already normal skin tone. So here’s how they did it: Instead of rubbing makeup off, Maguire rubbed makeup _on_ — a particular green color that could be isolated by the computer, and its hue altered to a skin tone, while the rest of the scene is desaturated. The completed illusion is quite convincing, though when you see the “how-to” sequence you may wonder how the actors did it without laughing. Anyway, I just wanted to give you a good place to go to look for a demonstration of the effect. ---
**Author:** ![Walloon](https://avatars.discourse-cdn.com/v4/letter/w/fbc32d/32.png) [@Walloon](https://boards.straightdope.com/u/Walloon)\ **Post date:** [July 20, 2003, 7:48am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/7 "2003-07-20T07:48:11Z")
[Restoring Disney’s _Pollyanna_](http://www.thedigitalbits.com/articles/robertharris/harris070102.html) ---
**Author:** ![SolGrundy](https://avatars.discourse-cdn.com/v4/letter/s/bbce88/32.png) [@SolGrundy](https://boards.straightdope.com/u/SolGrundy)\ **Post date:** [July 20, 2003, 9:51am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/8 "2003-07-20T09:51:58Z")
So if I can borrow the thread, here’s another one I just noticed today: in _Willie Wonka and the Chocolate Factory_, during the Oompa Loompa songs, they have the text “wave” onto the screen, kind of like an oscilloscope of a sine wave. The effect was really big in the early 70’s and late 60’s – I think _Vertigo_ and “The Outer Limits” series also used it. I know how you’d do it nowadays, but how was it done back then? ---
**Author:** ![GuanoLad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guanolad/32/42_2.png) [@GuanoLad](https://boards.straightdope.com/u/GuanoLad)\ **Post date:** [July 20, 2003, 11:38am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/9 "2003-07-20T11:38:54Z")
> [@](#): > > \*Originally posted by SolGrundy \* > \*\*in _Willie Wonka and the Chocolate Factory_, during the Oompa Loompa songs, they have the text “wave” onto the screen, kind of like an oscilloscope of a sine wave. … I know how you’d do it nowadays, but how was it done back then? \*\* According to [this page](http://www.kibo.com/rawdata/1999/1999-04-01.txt) (search for the word “Wonka”) it was a slitscan technique called Photo-Flex. I’m not entirely sure how it works, but they attempt to describe it in the article. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [July 20, 2003, 2:52pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/10 "2003-07-20T14:52:20Z")
[QUOTE] \*Originally posted by Walloon \* I’m a little troubled that you think that movies from the _1980s_ are creaky and need cleaning up. Anyway . . . [QUOTE] Well maybe the 70s. Still, unrestored films from the 80s seem to have a slightly grainier appearance than modern day films that have the benefit of digital color correction and whatnot. ---
**Author:** ![Wumpus](https://avatars.discourse-cdn.com/v4/letter/w/8c91f0/32.png) [@Wumpus](https://boards.straightdope.com/u/Wumpus)\ **Post date:** [July 20, 2003, 3:16pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/11 "2003-07-20T15:16:33Z")
A lot of movies from the 80s _are_ in need of cleaning up. Film is a pretty unstable storage medium. ---
**Author:** ![Zenster](https://avatars.discourse-cdn.com/v4/letter/z/cdc98d/32.png) [@Zenster](https://boards.straightdope.com/u/Zenster)\ **Post date:** [July 20, 2003, 5:26pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/12 "2003-07-20T17:26:49Z")
> [@](#): > > \*Originally posted by Cervaise \* > … So here’s how they did it: Instead of rubbing makeup off, Maguire rubbed makeup _on_ — a particular green color that could be isolated by the computer, and its hue altered to a skin tone, while the rest of the scene is desaturated. The completed illusion is quite convincing, though when you see the “how-to” sequence you may wonder how the actors did it without laughing. > > Anyway, I just wanted to give you a good place to go to look for a demonstration of the effect. Originally used in video, this is a process called “color keying.” It is what they employ to create the image screen behind television newscasters. In the newscast studio, all you would see is a bright blue panel on the set’s wall. The video editing processor is keyed to that specific hue and superimposes the live-action clip in that field. The color-key can be arbitrarily assigned to any shade, as in the movie example above. This can help to avoid people wearing blue for a specific scene or a closeup on a person’s blue eyes. ---
**Author:** ![chique](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@chique](https://boards.straightdope.com/u/chique)\ **Post date:** [July 20, 2003, 6:21pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/13 "2003-07-20T18:21:38Z")
1. How’d they make the ballplayers disappear into the corn field in _Field of Dreams_? 2. How do they make Jay Leno’s body disappear when he does that talking head/swami skit thingie? ---
**Author:** ![Duderdude2](https://avatars.discourse-cdn.com/v4/letter/d/cdc98d/32.png) [@Duderdude2](https://boards.straightdope.com/u/Duderdude2)\ **Post date:** [July 20, 2003, 6:30pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/14 "2003-07-20T18:30:00Z")
Chique, both of the examples you mentioned were achieved with green screen (I’m guessing). 1. In Field of Dreams, they shot the cornfield with no one there, then shot a separate scene with the baseball players walking towards a green screen. The then edit out the green so the background is now transparent and overlay this image on top of the cornfield image, so it now looks as if they’re walking towards the cornfield. Then thy simply fade the overlay so it looks like then disappear. 2. I haven’t scene the segment you speak of, but I can guess how it was done. Either they just have a camera focused only on Jays head, or they have Jay wearing a “Green” suit, which they can edit out of the picture in real time, via computer. ---
**Author:** ![Trigonal\_Planar](https://avatars.discourse-cdn.com/v4/letter/t/0ea827/32.png) [@Trigonal\_Planar](https://boards.straightdope.com/u/Trigonal_Planar)\ **Post date:** [July 20, 2003, 7:00pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/15 "2003-07-20T19:00:42Z")
Okay, I’m fairly knowledgable in film production techniques; obviously they “film it in colour and then make it black and white except for the part they want in colour.” This isn’t particularly informative. HOW is this done? Do they have someone who goes through frame-by-frame outlining the areas to remain in colour? ---
**Author:** ![Walloon](https://avatars.discourse-cdn.com/v4/letter/w/fbc32d/32.png) [@Walloon](https://boards.straightdope.com/u/Walloon)\ **Post date:** [July 20, 2003, 7:33pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/16 "2003-07-20T19:33:50Z")
No, you no longer have to manually create an outline mask for every frame. Computer imagery software is “smart” enough that, after you manually tell it where the outline of the figure is for only a few selected frames (depending on how much movement is involved), it will be able to follow that outline through the shot, even as it moves. ---
**Author:** ![censored](https://avatars.discourse-cdn.com/v4/letter/c/35a633/32.png) [@censored](https://boards.straightdope.com/u/censored)\ **Post date:** [July 20, 2003, 7:34pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/17 "2003-07-20T19:34:58Z")
> [@](#): > > \*Originally posted by Trigonal Planar \* > \*\*Okay, I’m fairly knowledgable in film production techniques; obviously they “film it in colour and then make it black and white except for the part they want in colour.” This isn’t particularly informative. > > HOW is this done? Do they have someone who goes through frame-by-frame outlining the areas to remain in colour? \*\* Most likely. The person who does this is called a rotoscoper, which is an entry-level job in the CG fx industry. This person draws a line, called a mask, around the areas that are to remain in color, but it isn’t necessarily frame by frame, as the rotoscoper can use and animate that line to follow the outlined shape in successive frames. If the shape is rapidly moving and changing, the mask may have to be done frame by frame. This is done in a compositing program, many of which are customized and in-house to the particular effects house, but the industry in general is dominated by [discreet](http://www.discreet.com)’s products, such as flame and inferno. **chique** , I haven’t seen Field of Dreams, but by **Duderdude2** ’s description it also sounds like they didn’t need to bother with shooting over green screen, only to shoot a clean shot (called a plate) without the actors with the same camera movement, angle, position, etc and then dissolve into it. Using keying in that situation may be unnecessarily complex. ---
**Author:** ![merrily](https://avatars.discourse-cdn.com/v4/letter/m/ac91a4/32.png) [@merrily](https://boards.straightdope.com/u/merrily)\ **Post date:** [July 20, 2003, 10:07pm UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/18 "2003-07-20T22:07:15Z")
Okay, how do they do the 360 degree fight scenes, where the scene is frozen and the camera swirls–typically, with someone in mid-leap or mid-kick? ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [July 21, 2003, 12:03am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/19 "2003-07-21T00:03:13Z")
> [@](#): > > \*Originally posted by merrily \* > \*\*Okay, how do they do the 360 degree fight scenes, where the scene is frozen and the camera swirls–typically, with someone in mid-leap or mid-kick? \*\* You mean like Bullet Time in _The Matrix_. Since that was the movie that originated it, see the extra features on the DVD for the details, but the basic answer is they used an array of 35-mm still cameras. Using modular hardware, 150 or so cameras were arranged according how you wanted the point of view to move in the scene, say tight on the characters, then a pull back and rise as you move in a circle, then back in tight 270 degrees from the starting point. The cameras poke through green panels which, as has been mentioned earlier, can be edited out, leaving only the characters’ images, and there are regular motion picture cameras at either end of the array. The movie cameras are cranked up, then the still cameras fired in sequence as the actors do their thing (over and over again) and you pick the best looking sequence. The background behind the caracters os 100% CGI so that the virtual camera can match its movement with the array’s virtual movement. In practice, it’s even more fiddly. You’ve got 150 lenses, each of which is a bit different than the others, 150 different exposures, maybe even a couple different film stocks. Everything needs to be smoothed over and matched up in the final edit. One can only wonder at the cost. DD ---
**Author:** ![GuanoLad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guanolad/32/42_2.png) [@GuanoLad](https://boards.straightdope.com/u/GuanoLad)\ **Post date:** [July 21, 2003, 12:18am UTC](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695/20 "2003-07-21T00:18:13Z")
> [@](#): > > \*Originally posted by DesertDog \* > \*\*You mean like Bullet Time in _The Matrix_. Since that was the movie that originated it. \*\* Urgh! They _perfected it_ (and made it a phenomenon), they did NOT originate it. [Next page](https://boards.straightdope.com/t/how-do-they-do-this-special-effect/189695.md?page=2)