Compositing in the modern digital age has two main areas of use; one is removing selected parts of an image to be replaced by another. Modern digital software can select a colour range on the image to be replaced or removed with ease, this is commonly referred to as blue screening – the pure blue being selected purposely to be removed (such colours do not generally appear in nature making the software’s job easier and more precise). This has many practical uses in television and film, a very common application would be a news weather report. The weather reporter stands in front of a blue screen and the weather map is composited on.
The second areas of compositing effects are adding an element, for example a cgi character, to an image so it appears seamlessly integrated. This requires more complex lighting and colour matching, as well as a believably created CGI scene/character. A good motion picture example would be ‘Terminator 2’ the T-1000 character can turn to liquid metal. Such a character which reflects the scene on all sides requires a long process of correct colour, lighting matching – but the results speak for themselves.
Past Composite Techniques (Which Digital has replaced);
‘Physical - In physical compositing the separate parts of the image are placed together in the photographic frame and recorded in a single exposure. The components are aligned so that they give the appearance of a single image. The most common physical compositing elements are partial models and glass paintings.’
‘Multiple Exposure - An in-camera multiple exposure is made by recording on only one part of each film frame, rewinding the film to exactly the same start point, exposing a second part, and repeating the process as needed. The resulting negative is a composite of all the individual exposures.’
‘Background Projection - Background projection throws the background image on a screen behind the subjects in the foreground while the camera makes a composite by photographing both at once. The foreground elements conceal the parts of the background image behind them. Sometimes, the background is projected from the front, reflecting off the screen but not the foreground subjects because the screen is made of highly directional, exceptionally reflective material. (The prehistoric opening of 2001: A Space Odyssey uses front projection.) However, rear projection has been a far more common technique.
In rear projection, background images (called “plates”, whether they are still pictures or moving) are photographed first. For example, a camera car may drive along streets or roads while photographing the changing scene behind it. In the studio, the resulting “background plate” is loaded into a projector with the film "flipped" (reversed), because it will be projected onto (and through) the back of a translucent screen. A car containing the performers is aligned in front of the screen so that the scenery appears through its rear and/or side windows. A camera in front of the car records both the foreground action and the projected scenery, as the performers pretend to drive.’
Today modern digital compositors are a vital part of the film making process; however like many key cogs in a machine, they usually go unseen. Despite the lack of celebrity prospects I’m very interested in compositing, so this website is about my research into it. Many recent Hollywood blockbusters rely on heavy CGI use, this is great news for all compositors, as their skills are in demand, with many to choose from my tutor suggested I look at the Transformers series.
In these films giant robots battle each other, fight humans and interact with the environment all seamlessly, this is a perfect example of the importance and quality of modern digital compositing. At the end of my research I hoped to be able to apply the knowledge id gained in attempting to composite an element into my own scene. Now this didn’t necessarily have to be a giant robot, what I want to try and understand & apply are the ‘camera matching’ and other techniques. Key techniques that need to be used correctly in order to give a realistic effect, in the case of transformers this is giant robots wreaking a city, but for me it could just be simple shapes.
No comments:
Post a Comment