Rotoscoping is often a last resort if a key isn’t working because it is a very time consuming process. Roto mattes are usually animated, often frame by frame. The process of rotoscoping (roto) is when you remove an object by drawing a matte around it. Mattes can be used to remove or isolate anything, and their shape, size and position can be fixed or animated. Often when keying, you’ll need to use a matte to prevent an area from being affected by a chroma key. You may also want to save it as uncompressed or with lossless compression to preserve your image quality and to make your compositing easier.Ī huge error that many filmmakers make is thinking that it is cheaper and easier to fix all production problems in post. A video file that is RGB + Alpha will save your color and alpha channels. If you key a shot and want to save it for later, you need to use a file format that supports alpha channels so the transparency information is not lost. This transparent area is referred to as an alpha channel. When a key is pulled, the green area of the shot becomes transparent. This is why it is important to control exactly how much green you are keying out so you don’t remove parts of the image you want to keep while removing the green screen. In other words when you key out a green screen, you are inherently getting rid of everything that is that color green in a shot. When you chroma key, the computer program takes all of a singular color or luminance value and removes it. Before we get into some common lighting problems, let’s take a look at how chroma keying actually works. Compositing is a multi-step process that often starts with a key or a rotoscope. It is a process that employs multiple skills including keying, color correction, rotoscoping, matting an object and lighting correction. Compositing includes adding things to shots, removing things from shots and painting things out from shots in addition to bringing shots together. Typically, compositing is the art of taking multiple images that were not captured together and blending the assets to make them look like they are one singular image. Keying is a compositing technique, but it’s not the only one. We'll also examine some common visual effects (VFX) techniques that can be used to fix bad chroma shots. Selecting a region changes the language and/or content on 'll look at some common problems and see how you can fix them while you're shooting. “Because editing capabilities change every few months,” explains Apley, “it’s important to be continuously learning.” As long as your lighting is set up correctly, there are countless ways to introduce fascinating new backgrounds to your projects within the world of chroma keying. Keep your eye on the latest tutorials and updates to Premiere Pro through resources like Adobe Live and try out new ways to use Chroma Key tools in your videos. Watch how they did it and see the stunning result of their work. Creative studio Abby Priest experimented to discover whether or not they could use liquid paint as a green screen. In your video editor, cut a simple matte (called a rubbish matte) between the person and the edge of the green area and remove the background beyond the line of the matte.Īnything solid in color can potentially be a screen for a keying project. Hold the pop-up screen behind the person or object you want to shoot. You can use these to shoot keyable footage on the go. Look for small, fold-out background panels that resemble a round section of green screen. Take it further with creative green screens. Just making that decision will save your project,” says Vavra. “As a beginner, it’s worth renting that hundred or so dollars’ worth of lights. You may also want to use a hair light to create a sharper line between your subject and background. These should be used to light the subject of your video. Next, get a 650-watt light and a 500-watt light, again with diffusion through a softbox or even white bedsheets. Vavra recommends renting two 1000-watt lights for lighting the screen itself and a method for diffusing, like softboxes, to put around them. The best types of lights for green screen footage. “That kit seems like it’s solving all your problems, but it’s introducing an entire world of new problems,” says producer and director Martin Vavra. These types of kits typically include one or two lights sufficient to light your subject only, which will create a patchy background that will be time-consuming and difficult to remove in your video editor. Cheaper green screen kits you can buy online are not going to cut it on their own.
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