Cinematography-Theory-And-Practice

SHOOTING PROCESS PHOTOGRAPHYGreenscreen/BluescreenChroma key, known as bluescreen, greenscreen, or process photography,is a method of producing mattes for compositing. The basic principleis the same for all processes and for both film and video: by includingan area of a pure color in the scene, that color can then be madetransparent and another image can be substituted for it. The peopleor objects you are shooting is called the foreground plate, and what youwill eventually put in to replace the green or bluescreen is called thebackground plate.Green and blue are the most common colors used, but in theoryany color can be used. There is one fundamental principle that mustbe remembered: whatever color you are using to become transparentwill be replaced for the entire scene. Thus, if the background is greenand the actor has bright green eyes, his eyes will become transparent.The color chosen for the process background should be one that doesnot occur in the foreground.If the foreground objects you are shooting contain blue or green,you can use another color for the background. What matters mostis that the background color be different from any color in the foregroundsubjects.If there is any camera movement in a matte shot, the post housewill most likely request that you include tracking marks (Figure 16.6).These can be as simple as crosses made of tape. They are placed onthe background itself as a clue to the movement that will be requiredof the background element that is to be laid in.The actors and props on the greenscreen set are called the foregroundplate; what you shoot to be the background by replacing the greenareas is called the background plate.Another important safety practice is to shoot a reference frame. This isa shot of the same green or bluescreen background without the foregroundelement — just the screen itself. This is useful in case there isany problem with the matte. Other recommendations include:noise into the image. 35mm is preferred over 16mm.ple,DV (digital video) is extremely difficult to composite.Keying software can deal with some smoke effects, but thereare limits. 5500K) at the beginning of each roll when shooting on film.this is that many camera lenses vignette slightly when wideopen, which can create problems with the matte.gain, which will increase noise. Never push film.groundplate with the focus set at where it would be if the foregroundobject was actually there. match. Use the same camera, or one with the same sensor size,the same lens, camera height and angle of tilt for both.groundplates; they must match the foreground plate.cinematography312