Creating Special Effects

Creating Special Effects

You're sitting in a movie theater. The lights dim, the music begins, and suddenly you are transported into a magical world, where things are happening, you've never seen before.
This is the art of special effects, the laborious work of many people, who gave their best to bring their director's visions to life.

To create special effects you follow a number of steps:


Design

The design-phase is the most important step in the whole procedure because in this phase the look of all creatures, landscapes and even the camera movements are defined once and for all.
First of all the characters, starships, creatures and landscapes used in the story are designed in rough sketches which are later developed into big colored pictures, which also lays down the size compared to other models. Then, a storyboard which illustrates the story with rough sketches is painted.
While writing the storyboard, containing pictures, dialoge, camera movements and all special effects, the sketches are transfered to the other sections like Model Construction and Mate Painting.


Model Construction

First of all, little prototypes of all models are built from simple materials. Such small-scale prototypes are very important because it's easier to correct little design-defects on simple models - at least, it helps to save time and money. Suppose the director isn't as pleased with the look of some models as the model makers had expected. Especially when working on a set of a spaceport as shown to the right it's much easier to rearrange the starships when they're made of paper.
In nearly all movies many models of the same object in different scales (from full-size to penny-size) are used so they can act together to create effects of relative size on the screen. For example, showing a starship beside a space station calls for a small starship-model, but combining it with live-action requires a full-scale model.
To create static models like starships you need a sturdy frame (mostly made of steel) which can carry the whole model and can be attatched to a rod when filming. Then the frame gets build-in lightning sources and is covered with plastics that shows exterior details. These plastics must be heat-resistance so that the models didn't melt when filming them iluminated by a powerful bank of lights (To create the imagination of a real object on the screen bigger than it's model, they often have to be filmed with high-speed-cameras requiring a bright light).
Creatures can be build as a costume operated from a guy inside (like Godzilla) or a puppet animated either by Stop-Motion, Go-Motion, some puppeteers or robotics (pneumatics, hydraulics or radio controlled). Puppets were built like starships in many scales: If a close-up for a head is called for, a Muppet-like version is used, animated by an operator's hand. In long shots, smaller versions made of clay (an armature inside allows them to move in their joints) are more useful. Commonly many models of the same creature in the same size are built, able to do different things: F.e. in Jaws there were three different full-size sharks: one swimming left, one right and the third swimming straight ahead (actual they had more models, but the others sunk).
Because full-size models often produce disappointing results, only parts of the creature like a hand or a tail are used when filming with real actors. Even in modern films with lots of CGI's like Jurassic Park, models are commonly used and are composed with CGI's.


Mate Paintings

Mate Paintings are used to complete scenes with a background like a building impossible to build or whole landscapes from other galaxies. Mate paintings are photo-realistic paintings, which were painted with oils and acrylics. They can be used in two different ways:
They are not only placed as a background in miniature sets behind the landscape and the models, they are also used to build the background for a live-action scene or even cover only several parts of a filmed scene to enlarge the set by not building it.
To compose the real action with the painting, there are several methods:
Rear Projection:
Working with rear screen projection, the painting is done on glass and contains an unpainted area similar to a window, where the real action took place. It's very difficult to create such a painting because in order to let the whole scene look real, not only the parts where the painting meets the filmed scene shouldn't be recognizable, all colors of the painting have to match the ones of the real action scenes. When composing the amte with the filmed live-action, a piece of frosted plastic is put behind the painting's window and the projector with the live-action scene is placed behind it. Now a second camera filmes the painting including the projected live-action from the front.
Front Projection:
Like above, the painting is done on glass with an unpainted area. A solid screen of Scotchlite (similar to a reflecting traffic sign) is placed behind it and the real action is projected from front on the picture while filming it from front, too.
Latent Image Painting:
The real-action scene is shot with the part later covered by the painting blocked off. Before the film is developed, a mate painting covering this previously blocked part is painted and is shot on the original film. Because you need no extra-projection the quality is outstanding.
Nowadays mate paintings are replaced by CGI's even allowing camera-movements during the scene, which are not possible with static mate paintings.


Miniature Photography

To let miniatures looking real, not only a detailed model is important: even the best model will not look good if it's not well photographed. This is caused by the diffused atmosphere, f.e. it makes a distant mountain looking hazy and desaturated. On miniature sets, bridal veil material replaces this atmosphere: Miniatures in different distances are seperated by bridal veiling (the closest ones had no diffusion, the second rank has one layer and the third another layer). This creates a more convincing picture as f.e. smoke.
When working with water, fire or smoke at miniature sets, the camera speed is also very important to let these things look real. For example the explosions in Independence Day only lasts a few seconds, but when filmed at high-speed, the action looks slowed-down (because the movie is shown at a constant frame-rate) and explosions are looking big and real. When filming miniature models which should appear bigger on the screen, the action is filmed at high-speed, too. Using this formula, miniature effects should look quite convincing:

f_filming = f_showing * sqrt ( D / d )
with f_filming = camera frame rate
f_showing = project frame rate (usually 24fps in the cinema, 25fps in PAL-TV and 30fps in NTSC-TV)

D = Dimension of the real Object (how it should look like)

d = Dimension of the miniature


Animation and FX

There are two different effects made with Animation: The first one is to enhance filmed pictures with new elements (f.e. additional glowing of the Lightsabers in Star Wars or additional lightening bolts in the background), the other one is to add non-filmed elements to a scene in order to let the scene look real (like shadows of seperately filmed models).
To create these effects, the film is projected frame by frame on a clear plastic sheet (cel) and is traced onto it. Then, the additional animation is painted with acrylics on the cel and gets combined with the live-action shoot by rephotographing it resulting in one frame of finished film. Because this process must be repeated for each frame, it's very costly.


Optical Composing

This is the last step in special effects production. Because this section is very technical I will only give a short summary:
Like the name says, this is where all different filmed shots are composed together. This includes different special effects shots as well as live-action shoots which should be put together with other scenes. To compose many filmed scenes, you'll need an optical printer, a camera that rephotographs and combines seperated images of film. Step by step one scene is put into the optical printer and is filmed, then the camera is rewound to the starting position and the next element is placed in the projector in order to get mixed with the last filmed, too. This process continues for each element until all are combined to one film. To avoid creating lucid images, the single elements don't have to intersect; this problem can be solved by using the blue screen process which applies the optical printer, too:
Real actors are filmed in front of a blue (green) screen and are rephotographed again with a special red filter which turns the blue background to black. This new background is used when exposing the actors in the optical printer in order to matte out the area where the background should be added later. To cover the area on the filmed background where the actors play, a reverse of this background is used resulting in a black silhouette of the actors (without this silhouette these actors look like transparent ghosts). Now these two non-intersecting scenes can be merged together in a double exposure creating the final picture.


    Book Sources:
  • Industrial Light and Magic - the Art of Special Effects by Thomas G. Smith, A Del Rey Book, Ballantine Books, USA-New York 1996
  • 20 Jahre Star Wars - offizielles Souveniermagazin, Blue Man Publishing, D-München 1996
  • Special Effects by Rolf Giesen, Edition Achteinhalb Lothar Just, D-Ebersberg 1985

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Tel.: (030) 46 79 64 43, EMail: ronald@comiczoo.de