Visual effect techniques also known as VFX, is the process in which imagery is created and/or manipulated outside the context of a live action shot. It combines live-action footage with generated imagery to create a realistic and believable effect, that would otherwise be too dangerous or expensive e.t.c to actually capture on film. Here are some examples.
Digital Compositing
Digital compositing is the name given to the process of assembling multiple images and combining them to create one final image. In this digital compositing showreel there are several examples of the process. For example the first clip shows an image of a man put against an image of a mountain. Obviously, to begin with the two images do not flow and it doesn't look like one whole image. However as the clip goes on, the different elements that are added for example snow, and darker colours, the image now appears as one and is more believable. This is digital compositing.
Blue and Green Screens
Effectively, blue screens and green screens do the same things. The main reason there are two options is that some things simply key better against one colour than the other. By filming something against a blue/green screen, it allows for a separate background to be chroma keyed in after filming. The reason these two colours are chosen is simply because they are the furthest colours from human skin, and so give the crispest effect once chroma keyed. In this particular video you can see that the first scene is completely green screen apart from the actor and a fence. This effect allowed this movie to create an epic war scene at sea, that would otherwise be completely out of reach for the film, and it really enhances the dramatic feel.
Computer Generated Imagery
Computer generated imagery, also known as CGI, is the process of adding computer graphics to create or add to a film sequence. In this particular example, CGI was used to create the famous moving pictures in Harry Potter. By doing this, it created a magical yet believable and convincing effect.
Mattes
A matte painting is something that has physically been painted onto the frame. This image is of Mark Sullivan, one of the finest matte painter of his generation. The piece of work here is a full-screen painting of Sigourney Weaver’s apartment building and surrounding cityscape for Ghostbusters II (1989). Everything in the frame was painted apart from the road which was left unpainted for later intersection of traffic e.t.c.
Morphing
Morphing is an effect in motion pictures and animations that changes or morphs one image or shape into another through a seamless transition. One of the first films to use this effect was Star Trek 6: The Undiscovered Country. Although the Star Trek franchise was the first to use the morphing effect, Willow (1988) was the first to boast an extensive use of morphing. Industrial Light & Magic created the visual effects sequences, which led to a revolutionary breakthrough with digital morphing technology. The way they used it in Willow meant that they were able to change one animal into another very seamlessly which made this particular scene incredibly entertaining.
Rotoscoping
Imagine having to cut a small piece of film digitally, then add in something else (for example the Star Wars lightsaber effect). Rotoscoping is essentially removing a piece of film and adding something in and sometimes this is even a frame by frame process. In this video from the Star Wars franchise, it shows how the “lightsaber” looks whilst filming, and then what it looks like post production, when the rotoscoping has been done.
3D Graphics
Also referred to as 3D CGI, 3D animation is a type of animation that uses computer generated images to create animated scenes. Compared to 2D animation, or traditional animation, 3D has much more depth, and it looks much more realistic. An animated scene starts with one picture, which is referred to as a frame. Disney Pixar’s Toy Story (1995) was the first ever 3D animated film. A innovating breakthrough in modern film making.
Special Effects Techniques
A Special Effect, also known as SFX, is a physical effect that is not added post production. This allows creators to simulate things that would otherwise be unavailable for a production. Here are some examples.
Mechanised Props
Mechanised props are machines (animatronics) or automatic devices used as props. A well known mechanised prop would be Yoda from the Star Wars franchise. The Harry Potter films use an array of mechanised props. For example Aragog, Buckbeak, and the weak Voldemort. This is a great effect, because unlike CGI, it gives the actors something physical to interact with, therefore not only does it improve the believability, it also creates a great overall effect.
Stunt Props
A stunt prop is a breakable prop made to be broken or mistreated. For example things made from sugar glass or balsa wood, that appear normal but are actually incredibly week materials and are easily broken. In this scene from James Bond, stunt cabinets made from both sugar glass and balsa wood, create a very realistic and exciting fight scene, full of drama.
Scale Models
A scale model is a full size replica of things , a well known example would be the Walker’s from “Star Wars”. This allows for a very realistic effect in films as physical objects are being used, therefore creating a more convincing effect.
Make-up Prostetics
Make up prosthetics are anything added to the body to enhance or add to a person. They’re more often than not made from latex. Examples of make up prosthetics can include anything from small cuts to a full mask added to the face. These make up prosthetics used in “Game of Thrones”, are one of the more detailed and dramatic examples of the effect, but show the realistic depth it adds to a production.