"What are the best approaches to have effective green screen footage?" In this research report will show the best approaches to have effective green screen footage. Firstly, mentioning about the research aim and secondly it will be focusing several specific areas about green screen such as; what are the blue and green screen in the media; what are the most effective green screen tools and compare the methods of green screen tools, what is the main rules of having effective Lighting the green screen and how to have effective shooting clean green screen footages. In this research report will be using several books and journals as resources in this research report.
It is going to mention to the research aim, in the final project there will be creating high quality short film with the group for the final project. In this project, it will be covered with many green screen footages and special effects. To achieve high quality and standard short film it needs to have good knowledge and skills about green screening. Furthermore, after the educational year's people might plan to be in the filming and design industry, to be a quality employee in this area they believe that it must have a really high standard final project. Another aim which is they want to achieve is the improving the skills and the knowledge about post production area. People believe that in this research report have done enough work and have got enough experience about editing footages and scenes with this research the knowledge and skills about green screen footages and adding special effects will be well developed and will be ready for next years in the industry.
The report is going to mention the research objectives one by one with separately titles;
What are the blue and green screen in the media;
Many people believe that one of the typical problems of filming is separation of a non-rectangular background image from rectangular background footage, it can be in a film frame, taking out of an actor from a background scene to allow substation of a different background. Of the several problems in this difficult and determined problem, groups tried only the special case of separating chosen foreground footage from a background of an endless, or almost constant, backup colour. This backup colour has often been blue, so the problem and its answer have been called blue screen matting. Though, other backup colours, for example yellow or green, have also been used, so people often simplify to endless colour matting (Beyer, May 1964). The mathematics of continual colour matting is offered and proven to be insoluble as generally experienced.People shall also prove that an algorithmic result is possible by allowing the foreground object to be shot against two constant backing colours actually, against two completely random backings so long as they everywhere. This interpretation has been supported in the works of Beyer (1964). Jeremy Hanke said that "I have done a lot of research into this subject as I have prepared for this book, but I am hard pressed to come up with a more concise description of the technology than the one given by effects filmmaker Zach from Fox's On the Lot: Green screening is just basically telling the camera to replace anything it sees as green with whatever you (the director) want (Jeremy Hanke, Michele Yamazaki, 2009)". Many people believe that to successfully composite an alive action actor with a digital location, the actor must be shot beside a uniform background that can easily be deleted in the composite. Those solid backgrounds are identified as blue screens or the more popular green screens. The colours green and blue are used because they are at the other side of the colour field from most sin tones. The computer is then able to select a limited colour range to mask out the background and create a silhouette of actor. This opinion has been supported in the work of David K. Irving, Peter W. Rea (2010).
What are the most effective green screen tools and compare the methods of green screen tools;
Firstly the report is giving little information about keying in the media world. Grund Hofer (2008, article 151) states that "Many people encode keying information in to the Y channel of our p-frames approaching a uniform luminance on the background surface. Since the p-frames are radio metrically compensated before being projected out, locally different surface reflectance properties are widely neutralized. Recording the p-frames and separating the Y channel will then show a consistent intensity at the background while the foreground objects are unlit, and therefore appear black". Let's focus the comparison between the Difference Matte and Chroma Key. Several of people believe that the term Chroma key is often used roughly to mean anything that refers to pulling a colour differences, at from film or video footage. Even several producers of matte compositing hardware and software still prefer to the process as Chroma keying. Though Chroma keyers have evolved to do basic keying quite well, the process refers to switching off certain colour pixels in an image or footage. Therefore, when selecting a green colour from the background in an image layer, the keyer looks for all examples of that green colour and switches them off or the keyer makes them see-through (Jeff foster, 2010). According to Jerry Hoffmann's book, people can come to this conclusion; Chroma Keyer is a more sophisticated filter that keys out any colour, including blue and green. Editors can even use it as a Luma keyer if they disable the colour and saturation and Jerry Hoffmann states that in the book "The Chroma keyer has the settings as the colour correctors limit effect controls. It also spill suppression built in. many people believe that it is much better than the earlier iterations of filters for this effect. When people look at the colour key, people can see that it is similar to the blue and green screen filter. It allows them to select any colour for keying. The colour picker control allows them to select which colour they would like to key out.it is great if what they are trying to key is blue or green, so using these colours as the background in preparation for key does not work well. About the difference matte, it compares two clips and key out areas that are the same. The view pop-up menu allows them to look at the source clips, the matter created by the filter, the final matted image, or a special composite of the source, matte and the final image for reference. The clip control allows them to specify another clip to compare to the current image for keying. The threshold and tolerance sliders allow them to adjust the key to try to isolate the parts of their image they want to keep. The Luma key is similar to colour key, except that luma key creates a matte base on the brightest or darkest areas of an image." Keying out luminance value works greatest when the image has a wide variance between what they want to key out and what they want to keep. When the editors or special effects artists use the blue and green screen key to key out the blue in a clip, there might be bit of undesirable blue colour around the edges of the key which is called spill. For this problem there are two tools which are they called Spill suppressor blue and green. Those suppressors help to remove the unwanted spills from the edges. This opinion has been supported in the work of Jerry Hofmann (2004).
What is the main rules of having effective Lighting the green screen
Many groups believe that the lighting is one of the most important at the same time the really hard processes in the media world. The main important point to capturing effective green screen footage is the lighting. If the green light weakly, editors will spend time in post-production trying to repair it. Joshua Paul (2005, pp.75) states that "Your actors should not wear anything green. When you go to matte out the colour green from your scene, you don't want to matte out portions of your actors! This same principal applies to your props, as well." Lighting is possibly the most important segment of correct blue/green screen production. If whichever the screen background or the subject isn't correctly lit, then the composite will be a tragedy. Even as forgiving as several keying plug-ins can be, the editors want to eliminate as many potential problems before people shoot to get the optimum conclusions and save time in compositing. People must be sure that they consistently light the background screen. If there are hot spots or shadows or even heavy wrinkles in the cloth, they will build problems in the composite. Except people are shooting outdoors with natural light, they should always use separate lights to inform the background from those used on their subjects. This view has been supported in the work of Jeff Foster. As it mentioned above good lighting is really important, the last thing people want to have shadows on their green screen, because shadows change the colour theirs computer understands and defeat the unified effects. Shadow cast by the actors themselves are particularly unsatisfying. The gamble is to light the background and the actor with different light sources. Whether or not they have great lighting, keep lots of space between their actors and the green background. Four feet is can countable as a decent law of thumb. This reduces the like hood of shadow messing up the effect their computer will apply. Many people believes that good lighting and lots of space also helps them avoid the dreaded halo when the lighting's poor or the actors are too close to the green screen, green light can reflect off their subjects. The outcome is a strange halo effect that makes it easier to tell that the subject is not really flying through outer space (David Pogue, Aoron Miller, 2009). Many green screen professional artists supports that in some cases, backlighting the subject is essential, which will create those pesky hot spots on the floor. When this effect is inescapable, a polarizing filter on the camera can be used to eliminate the glare from the floor. If people are starting to sense that lighting a green screen shot is a battle of conflicting problems. A similar trick that is sometimes used in film but that works just fine in video as well is the use of bema splitter and a glass bead reflective material such as 3M Scotcchlite or Reflec Chromatte. Often, green invisible set pieces will be included, especially when they are using the new simulated sets. A plywood cube of the proper height painted green can allow the actor to set objects down on a virtual surface. However, these set pieces present peculiar problems since they are difficult to light evenly and they are actually in the foreground zone, where people might be using a contrasty lighting structure. The top of the scene will gather more light and the object itself will throw shadows that must be removed either live or in post. One key is to use a darker shadow of the key colour on the top of the set piece than on the sides. Another is to use traditional lighting controls flags or scrims to control the amount of light on the top of the set piece (John Jackman, 2010).
How to have effective shooting clean green screen footages
Many people believe that the most problematic shooting condition for most amateur or intermediate videographers and cinematographers is blue/green screen Croma-keying production. This technique has been around for decades. It has been used for projects ranging from special effects in motion pictures and television to the meteorological graphics on the evening news. It is now possible for even the smallest budget production to have good results with a minimum setup in either a studio or outside. The key is to light the blue/green screen behind the subject evenly, without creating "spill" onto the subject or creating too much of a difference in background/foreground exposures (Jeff Foster, 2004). There are really important tips for shooting clean green screen footages. Some green screen materials, like poster board, come in the right colour but if they are shiny, they reflect white light in addition to green. Green fabric is preferable, because it diffuses light and minimizes reflections. If people are using poster board, just make sure they do not see any glare. Another tip is to eliminate shadows, the green surface has to be smooth. Wrinkles and bumps make the computer added background look wrinkled and bumpy, no one should be wearing green in the shot, at the end of the shot, shoot just few frames of the green background without their subjects in it. Do not stop the camera before the actors way out, however if they do that some software imports the key shot as an isolated clip, ruining their chances of putting it to any use. This interpretation has been supported in the work of David Pogue and Aoron Miller (2009). Creating a believable composite scene requires them to capture usable green screen footage. Although most software applications are capable of dealing with badly acquired footage, they shouldn't count on their application's ability. Simply put, if their shoot a bad green screen, don't be surprised if meet with a bad composite. Green screen refers to any background that consists of a single, solid colour, whether its green, blue, or some further colour they decide to use (Joshua Paul, 2005).
Conclusion
In summary of the research report, it would like to sum up the outcomes and the improved knowledge. In the research report It been used many information from several resources such as books, journals, articles, web sites, eBook and etc. It highly improved the knowledge about green screen and blue screen. Firstly It mentioned about the aim of the research and It believed that the research which It have done it will be really useful for the final project in the group because some people are creating a short film and people are going to use many special effects and green screen footages with video compositing. The techniques It have learnt many methods, keying techniques and tips of the how to manage to shoot clean green screen/ blue screen footages and green/blue screen lighting techniques about the set and the actual green screen itself. Furthermore it have compared the keying methods and found out the differences between keys. It believes that the research report pushed the skills and knowledge limits higher.
BIBLIOGRAPGHY;
1-BEYER, (May 1964)W. Traveling Matte Photography and the Blue Screen System. American Cinematographer The second of a four-part series, p.266
2- Jeremy Hanke, Michele Yamazaki, (2009), Green screens Made Easy: Keying and Compositing Techniques for Indie Filmmakers, Michael Wiese Productions, and p.2
3- David K. Irving, Peter W. Rea, (2010), Producing and directing the short film and video By David K. Irving, Peter W. Rea Focal Press, p. 263
4- Grund Hofer,(2008),ACM Transactions on Graphics, Vol. 27, No. 5, Article 151, Publication date: December 2008.
5- Jeff Foster, (2010), The Green Screen Handbook: Real-World Production Techniques by John Wiley and Sons, pp.24
6- Jerry Hofmann on Final Cut Pro 4 by Jerry Hofmann, pp533, New Riders, 2004
7- Joshua Paul, (2005), Digital video hacks, O'Reilly Media, Inc., pp. 75
8- Jeff Foster, (2004), After Effects and Photoshop second edition 2004 SYBEX Inc. published in Canada, p. 156
9- David Pogue, Aoron Miller, (2009), IMovie '09 & IDVD: The Missing Manual, O'Reilly Media Inc., pp. 146
10- John Jackman, (2010), Lighting for Digital Video and Television, Focal Press, pp. 210
11- Jeff foster, (2004), After Effects and Photoshop Second Edition, 2004 SYBEX Inc. published in Canada. Pp. 153
12- David Pogue, Aoron Miller, (2009), IMovie '09 & IDVD: The Missing Manual, O'Reilly Media, Inc., pp. 146
13- Joshua Paul, ( 2005), Digital video hacks, O'Reilly Media, Inc., pp. 76
14- Figure 2.14, Digital video hacks By Joshua Paul pp. 76, O'Reilly Media, Inc., 2005
15- Figure 5.18, Peachpit Press, 2009, Video Made on a Mac: Production and Postproduction Using Apple Final Cut Studio and Adobe Creative Suite, Richard Harrington, Robbie Carman, pp.104
16-Figure 5.19, Peachpit Press, 2009, Video Made on a Mac: Production and Postproduction Using Apple Final Cut Studio and Adobe Creative Suite, Richard Harrington, Robbie Carman, pp.104
17- Figure 2.6, - The Green Screen Handbook: Real-World Production Techniques By Jeff Foster pp.23 John Wiley and Sons, 2010
18- Figure 16.7, Producing and directing the short film and video By David K. Irving, Peter W. Rea pp. 264 Focal Press, 2010
19- Figure 16.8, Producing and directing the short film and video By David K. Irving, Peter W. Rea pp 264 Focal Press, 2010
20- Figure 5.9, Peachpit Press, 2009, Video Made on a Mac: Production and Postproduction Using Apple Final Cut Studio and Adobe Creative Suite, Richard Harrington, Robbie Carman, pp.98
