When you’re dealing with CG, there are two “art environments,” so to speak. There is the 3d world in which objects are modeled and animated, and there is the 2d world of the screen. Things are getting a little blurry in that regard, what with stereoscopy becoming more prevalent and 3d functions becoming available in the compositing software, but it’s still a somewhat useful division with regards to categorizing artists.
- Compositor: The goal with most visual effects is to make it look as though the computer-generated images were physically present when the scene was being shot. The intention is for us to believe that Obi-Wan and Anakin are really fighting each other on the shores of a lake of lava. The reality is that the actors were on a bluescreen stage, and their lightsabers were just colored sticks. The compositor receives the various pieces of the shot (green/bluescreen footage, matte paintings, rendered 3d elements, and more), and combines them into a single image that appears as though all of those things were actually in the same place to be photographed.
- Rotoscoper/Roto Artist: Every element in an image that gets manipulated separately needs to be isolated from the rest of the image. The roto artist creates moving mattes that cut out a given object or character so that it can be treated as a discrete object. There is no end to the reasons this is necessary, but a quick example is: Starbuck walks in front of a Cylon Centurion. The Centurion is a CG character that, under normal circumstances, can only be placed on top of the video footage. In order to make it appear as though it’s behind Starbuck, it needs to be occluded by her body. So the rotoscoper would make a matte around Starbuck and use it to hide the Cylon as she walks in front of it. The matte is just a white shape on a black background that silhouettes the actress. Roto is a very common entry-level position that can lead to a career as a compositor.
- Paint artist: Any time an object needs to be removed from a shot or a background needs to be reconstructed for some reason, a paint artist is given the task of getting it done. The most obvious application of this skill when an actor in an action movie is held up by wires. Someone must remove the wires (a job appropriately called “wire removal”) and other harness from the shot, and that’s the job of the paint artist. Paint is another common entry-level job.
- Dustbuster: Some paint artists are given the task of removing artifacts of the filming and scanning process from the frame. If there was a drop of water on the lens (like one of the shots from my student demo reel) or dust on the film scanner or a hair in the camera gate, someone has to paint those blemishes out. Again, dustbusting is a good place to get a start in the industry, although usually it’s wrapped up with the paint artist role.
- Matte painter: Usually any time you see a breathtaking view in a movie, what you’re actually looking at is a painting. Matte painters create backgrounds and set extensions so that a scene shot in a backlot can look like it was shot at an expensive location. Or on the moon, or in Middle Earth, or on Coruscant. These days, matte painters also need strong 3d skills to add additional life and depth to their paintings.
- Digital Intermediary/Colorist/Finisher: Strictly speaking, the DI is in a completely separate part of the production chain, but the skills have a lot of overlap with the compositor, so I’m putting it here. A colorist’s job is to control the ultimate look of the product. During the editing process, the colorist may color correct individual shots so that all of the cuts look the same, but a lot of the time the editor does that. Once the edit is done, the digital intermediary creates master color corrections for the entire piece, and sometimes additional color treatments for individual scenes, in order to create a style. For instance, the slight greenish tinge of the Matrix or that golden, yellowed paper feeling of the Indiana Jones films are effects created by the colorist. In addition, the DI conforms the product to whatever color space and format is appropriate for creating a master print.
- Depth Artist: A new entry-level position, the depth artist creates 2d images that describe how far a given pixel is from the camera for the purposes of stereoscopy (“3d movies” in the vernacular). The depth map looks like a gray-scale image where the brightest points are closest to the viewer and the darkest points are furthest away. This is a critical component of converting 2d movies into stereo movies. Even movies that were originally shot in 3d, though, will often need some additional work to perfect them, and a depth artist will assist in that process.
- Stereographer: A stereo movie requires an artist who understands the specific stereo-related issues that arise at all points in the production chain. The stereographer will be on set to make decisions such as how far apart the camera lenses should be and at what point the images should converge. They will also be involved in post-production, supervising stereo compositors and editors to achieve a pleasing 3d result.
- Stereo Compositor: 3d movies require some specialized skills that are not necessary for traditional films. The stereo compositor does the same things as a normal compositor, with the addition of controlling the 3d experience of the viewer.
- Lookdev: Look development is a hybrid of the compositor with the concept artist. When it’s important to get an idea of what an effect should look like before work begins, the lookdev artist creates style frames and sometimes short animated effects to make sure the effects team understands what the client wants.
These processes are not limited to film and integration with live-action material. Compositors often work alongside motion graphics artists for CG commercials or help to make game cinematics. Matte painters might even be involved in creating backgrounds for game levels.
In addition, there is a degree of stratification in these jobs. That is, there are several levels of compositors: Junior Compositor, Compositor, Lead Compositor, Compositing Supervisor, 2d Supervisor. The same holds true in most film production jobs.