When you watch a modern blockbuster, you can see the characters in many different places. But how do they do it? After all, these movies aren’t shot on another planet, in completely different places? Or are they filming? In fact, everything is simpler. When shooting films, chromakey is often used. Let's see what it is and how to work with it.
What is chromakey?
Chromakey– a film-video shooting technique that allows you to replace the background of an object. Widely used by filmmakers to create various film effects, mainly to move the subject to another location. That is, if you see in a movie that Spider-Man is crawling along the wall of a skyscraper, then know that in this case, the chromakey effect was probably used.
You may be wondering, “Why use a green screen or blue screen?” It's simple. Separating the background from a person in a video is much easier if the background is made of a solid color that is not found in human skin tones. And these are, first of all, blue and green colors. (Remember, we are talking about living people from planet Earth here.)
The practice of background subtraction may seem difficult at first glance. But in fact, everything is quite simple here.
Can a beginner do this?
Removing and replacing the background on a video sounds complicated, doesn't it? Okay, stop! Not to worry! This used to be difficult when using films. But now, in the digital era, everything is much simpler. Here's what you need to get started:
- Digital camera. You already have one, right? In principle, almost any modern smartphone will do.
- Computer. It doesn’t matter, you can use Windows, you can choose a Mac, you can choose Linux. By and large, you can even use a phone or tablet, but still, a computer will be better.
- Cable to download images from the camera to your computer. (Duh.)
- Software. Not a problem either. In this article, you will find a number of free programs for video editing. So, you don't even have to pay for this. Although there are paid solutions too.
- Green or blue background. And of course, you need the background itself. You can buy it, or make it yourself. It all depends on your imagination and your capabilities.
You can paint your background using Chroma Key paint. This option requires physical labor, but is the most common option.
Another option is to put up a green screen. You will need stands and clamps.
Material options include paper, muslin fabric, or foam-based fabric (often used for car headliners). The latest fabric prevents wrinkles during use.
There are also smaller folding screens that are convenient for outdoor photography and tend to withstand wrinkles.
- Digital backgrounds. Of course, it’s not enough to remove the background. We need to put something else in its place. For example, instead of your home, put a background of nature, maybe other cities. Or maybe you want to insert your hero into real historical events, as the famous director Robert Zemeckis did in the film “Forrest Gump” (if you haven’t seen this film, be sure to watch it). Well, maybe you want to move your hero to Mars? None of this is a problem. Here is a selection of sites where you can take videos for editing and use them in your works.
How to shoot chromakey?
Here summary 7 Key Elements to Creating Great Green Screen Videos.
Distance
Since using a green or blue screen entails using a physical object behind your subject, you need to pay attention to how much distance there is between your subject and the background.
- Make sure your subject is far enough away to avoid shadows on the screen behind them.
- When shooting close-up heads only (head and shoulders only) your subject can be positioned closer to the green screen.
- For shooting in full height, not only will your subject be further away from the screen, but you'll also want to shoot from a certain distance, which will give a natural appearance and prevent distortion.
Correct lighting
When lighting a scene, you should focus on lighting the screen and the subject independently. That is, you need to separately illuminate the background and separately illuminate the subject. You can combine lighting, but this may result in shadows on the screen.
- First, focus on lighting the screen evenly without your subject.
- For light sources you can use LED lighting systems, fluorescent lamps.
- You can use your camera's zebra settings to check if your screen is evenly lit.
- Then light your subject. Focus on lighting it in a way that matches the scene you'll be putting in post-production.
Working with captured video in a video editing program.
The post production software you use will have great value for the scene you will be doing. Quality software can make a good video even from mediocre material.
- Adobe After Effects- an excellent platform for compositing.
- KeyLight, the plugin that comes with After Effects, comes with many features that help you pull out a good scene.
- If you can't pull a good key out of the entire frame, try using an After Effects technique called garbage matting, in which you can select the part of the shot that works well and eliminate the minor, more low quality movement around this part.
- Make sure your object is not being moved to garbage matting.
Bravo! You did it! As you can see, making an effect with a phono replacement is very simple! Yes, there are a few features, but nothing complicated. Doesn't it look great?
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So, let's start in order.
What is chromakey? In simple language, this can be explained as follows: combining two or more images into one. How? Let's look at the top picture. As we can see from behind, the girls placed a green background, then through the program it was removed and replaced with a beautiful landscape. The background doesn't have to be green, it can be blue, red, white...anything. The main thing is that it is ONE COLOR. But it is still preferable to use Blue or Green (it is better separated from the person), red color is less suitable (it is more difficult to separate from the object), because our skin has a reddish ruddy hue and it can also stand out.
You can notice that the floor at the girl’s feet was not cut out. This happened because its color is different from the background. As a rule, to avoid this, a plain material is also laid on the floor. Or simply change the camera angle so that there is nothing superfluous in the frame. It should be noted that the model’s clothing should not have a similar color, otherwise it may also be cut out along with the background, and we do not want this. It is also important to set the light correctly so that there are no strong shadows or overexposures in the background (they can also cause problems with highlighting). When working with chromakey, maximizing color differences between the background and the subject is very important. What material should the background be made of? It can be either fabric or paper. It depends on what kind of shooting you are going to do and in what conditions. In nature, on the street, it is natural to use a chromakey background made of fabric, if only because it is more durable and transportable (it can be easily rolled up and put in a bag). Paper backgrounds are very popular in studios. The main advantages of a paper background are its lack of texture, dullness and elasticity. They do not create glare from the light. But as a rule they have large dimensions. They get dirty and spoil faster. There are also non-woven backgrounds (regular and velvet), which are a synthetic fabric. Despite the fact that they, like paper ones, are not very convenient for transportation, they have high abrasion resistance and stability. The background is installed on special frame structures, brackets with holders.
But chromakey is not just about replacing the background. With its help you can replace anything, there are even special suits.
Having put it on, the person can be replaced with some 3D monster or something else....depends on your imagination)
Chroma key is very actively used in the film industry. Nowadays, not a single cool film is made without him. What's easier: to go to Alaska with a film crew? Or film an actor in a studio, and then substitute him in a finished video footage with the same mountains from Alaska? But for professional keying and equipment with software must be appropriate.
Here are some examples of professional use of chromakey:
It is also very widely used on television. In some kind of weather forecast, where behind the presenter there is a touch panel with clouds and the sun. Or in a news program where the presenters sit in a virtual 3D studio.
Chroma key can be ordered from an online store (for example www.foto.ru) or in a store in your city that specializes in video and photographic equipment, studio equipment...etc. Perhaps the cheapest paper background can be purchased for 1000 rubles. A fabric background with a folding frame will cost about 3,000-5,000 rubles. Non-woven backgrounds are most in demand among novice photographers due to their low cost. For example, a background measuring 1.5x2m will cost only 1000 rubles. And 2x5m 2000-2500 rubles. Remember that the cost directly depends on the size of the ordered canvas, the material and your city.
Hello friends.
I think it’s no secret to you that many videos (both television and home) are initially filmed on a green (or blue) background, and then this background is removed in a video editing program and any suitable background is substituted in its place.
Here is a clear example of what it looks like before and after using this technology.
Why green or blue background?
Everything is simple here.
The fact is that it is these shades of colors that are absent in the color of human skin, which means that removing such a background will be quite simple. And after removing the background from your video or photo, the character's skin will not be harmed.
However, the main condition here is: When shooting, the character should be dressed in such a way that his clothes do not contain the same colors.
That is, if you are shooting on a green background, then the character’s clothing should not contain green, otherwise it will also be removed.
In general, you will have to tinker a lot with this material...
The same situation applies to the blue background.
So, such a background, which you subsequently completely remove, leaving only the character in the frame, is called chromakey.
Where to buy chromakey for your home studio?
Let's start with the fact that there are specialized offline stores and online stores with photo and video equipment, where you can easily find and purchase such a background. Usually it is quite large in size, since it is designed for professional studios. These backgrounds are also not cheap, I must say.
But what if you need a relatively small chromakey and want to save money?
There are several options for solving this problem:
1.
You can select a wall (or part of a wall) to shoot against and paint it green. It is only important that the painted wall does not reflect light from lighting fixtures. But you remember what?
Because if your homemade background shines or glares, then you will have a hard time removing it.
This method seems to be quite good, if not for one big but: not all of us can afford to dedicate a wall for this purpose.
2. You can go to a fabric store and buy a thick matte green fabric and hang it on the wall. The main thing here is to choose a fabric of sufficient density, as well as tone and color saturation.
3.
Well, the third way is to look for resources where you can purchase ready-made chromakey at a reasonable price.
I would even say quite moderate.
This is the third method I will share with you.
More precisely, I will share with you the resource where I myself purchased a good and very inexpensive chromakey.
And where do you think I bought it?..
On the well-known Aliexpress website to all of us!
So, I'll start with what I bought. green background I here from this seller. And my purchase reached me safe and sound.
I received this package with my background in the parcel:
When unfolded, if I’m not mistaken, it measures 1.6 x 3 meters (but, I must admit, I didn’t measure it).
These sizes are in most cases quite sufficient for a home studio. For example, this section completely covers the opening of a swing double door.
True, I still don’t really understand what exactly this background consists of, I mean in terms of its structure. You know, it's either paper or fabric.
But I would like to draw your attention to the fact that I would advise you to handle it with care.
Try not to wrinkle or scratch too much, machine washing is out of the question!
It also won’t be possible to smooth it out without problems with an iron; it’s better to let it hang loose. Or, even easier, gently stretch it so that wrinkles are minimal.
Well, that's all I wanted to tell you today.
In conclusion, I will say that you can choose any of the options presented in this article for purchasing chromakey for your creativity. Just be sure to take into account all my recommendations for each of them.
Well, as for background from Aliexpress…
I will say that this is a very good option for equipment for your small home studio! It meets all standards and requirements and copes with the task very well. But of course when proper lighting and further steps to remove it in a video or photo editor.
That's all. I will be glad if my article was useful to you.
And good luck to you in your creativity!
Your Victoria
Chromakey
Shooting a scene on a blue background
Chromakey(English) chroma key, literally “color key”) - a technology for combining two or more images or frames in one composition, color keying (or keying), used on television and in modern digital film production technology. During filming, the subject is placed on a plain colored background. When combining a subject with a background in a frame while recording a scene or during editing, you can place another image in place of the background. Also in everyday life chromakey They call it the rear screen itself, against which they are filming.
The most common colors used in keying are green and blue (cyan), because these colors are not found in human skin tones. However, almost any color can be used, including white and black. The most popular background color for combined filming in film production is green (which gave the technology its name “ Green screen"), for television programs a blue background is more often used (" Blue screen"), although the color of the key screen depends on the creative task set by the director and the characteristics of the equipment on which key projection is performed.
Another common name for the technology is keying(English) keying, color keying). It is also worth noting that the correct pronunciation chromakey is “kromaki”, but it has not taken root on Russian-language television and the jargon “chromakey” is now in use.
The only disadvantage of chromakey is that if a person’s clothing has a color similar to the background color, then the person begins to “shine through” (“glow”). Therefore, when choosing a costume for an actor or TV presenter, they try to avoid colors that match the background. In cinema before the advent of television technology and digital ways Film production used methods of combining the actor's scene with the background, known as “rear projection”, “front projection” and “wandering mask”, giving a pictorial effect similar to chromakey.
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Synonyms:See what "Chromakey" is in other dictionaries:
Noun, number of synonyms: 2 rear projection (2) background (26) ASIS synonym dictionary. V.N. Trishin. 2013… Synonym dictionary
Scheme of the second exposure using the wandering mask method. And an undeveloped negative film with a hidden image of the actor; B developed film with silhouette mask; C lens; D background landscape Wandering mask is a type of film t... Wikipedia
Special effect, special effect (English special effect, abbreviated SPFX, SFX or FX) is a technological technique in cinema, television and computer games, used to visualize scenes that cannot be filmed in the usual way... Wikipedia
- (from the English rear screen, abbreviated “rear”) a single-color background (a piece of fabric or a special sheet), which is located behind the actors and/or subjects during filming. Using chromakey technology, the colored background is replaced in... ... Wikipedia
Green screen (chromakey) is a type of special effects technology. Special effect, special effect (English special effect, abbreviated SPFX or SFX) is a technological technique in cinema, television, shows and computer games, used for ... ... Wikipedia
Rear screen (from the English rear screen, abbreviated as “rear”) is a one-color background (a piece of fabric or a special sheet), which is located behind the actors and/or subjects during filming. Using chromakey technology, the colored background is replaced during filming... ... Wikipedia
Green screen (chromakey) is a type of special effects technology. Special effect, special effect (English special effect, abbreviated SPFX or SFX) is a technological technique in cinema, television, shows and computer games, used for ... ... Wikipedia
Rear projection scheme when filming actors in the scenery of a moving car Rear projection, Rear projection is a technology of combined filming, widely used in classical technology ... Wikipedia
Today we dive into the history of visual deception in Hollywood. She is also a backstory modern composition the so-called green screen (Green Screen) or chromakey (Chromakey).
Magic screen
Now that video cameras and computers are everywhere in modern world, it's easy to forget that the first motion pictures were themselves special effects. Here, at the beginning of the film industry, we will begin our journey. The end of the 19th century, one of the first world cinematographers, creating several films a year, a man who spent his entire life studying the art of illusion - Georges Méliès.
Georges Méliès
In his film A Man Has Several Heads (1898), Méliès uses a visual trick that is the germ of what we now call green screen composition. Using "matte" for different exposures.
Composition is a way of combining different frames and elements into one image. The matte shot was the first composition technique used by early filmmakers, including Méliès.
In his film, Méliès darkened some parts of the frame with glass and black paint. This "matte" prevented light from reaching the film, preventing it from being exposed. Méliès would then rewind the film and darken everything else, revealing only the part of the film that was underneath the matte finish. The resulting double exposure combined several frames in one. And this was all done inside the camera.
Train
This matte technique was also used in Edwin Porter's 1903 film The Great Train Robbery, but not as a magic trick, but as a way to create a larger, more realistic world.
Note the moving train outside the station window, as well as the open postal car door with the landscape in the background. Both of these shots were done using matte and double exposure.
A natural question arises: “Why didn’t they just film in a real station or train carriage?”
The fact is that at that time it was technically impossible. The first orthochromatic films required a lot of light. And the technology of electric lighting necessary for film will only be invented in a couple of decades. Not to mention the obvious exposure issues that come with shooting indoors and having a window in the frame. Even now, the camera may have problems with brightness differences between indoors and outdoors. In order for the film to look and feel natural, we had to use visual trickery.
During the 1900s and 1920s, the film industry evolved and new ways were developed to expand film sets and create artificial realities.
“Glass shot” is a technique of drawing elements on glass that was placed between the subject and the camera. It's a kind of "natural" composition, perfected by early cinematographer Norman Down. He used it on film sets, visually enlarging and changing them without the expense of construction.
ONE OF THE FIRST CINEMATOGRAPHERS NORMAN DOWN
The disadvantage of using a "glass frame" was that the images had to be ready to shoot. Norman Down solved this problem by painting the glass black and using this frame as a "matte". He then inserted the film into the second camera. After which, the matte artists could paint the background images without haste. This method of drawing "matte" was also used in the golden era of Hollywood. In general, it is still used today, even in the modern digital world.
JAMES CAMERON WORKING ON THE GLASS FRAME FOR ESCAPE TO NEW YORK (1981)
"Black screen
The disadvantage of "matte" is that the camera must be completely still. Nothing should cross the invisible matte line between the actual action and the background image. This is how the moving “matte” appeared.
In 1918, Frank Williams patented and demonstrated in the film Sunrise by Friedrich Wilhelm Murnau (1927) the process of using black "matte". In it, objects were shot against a completely black background. The film was then copied onto very high contrast negatives until it was developed black and white silhouette. This black and white silhouette was used as “matte”. It was called a moving "matte" because it moved along the frame.
This "black-and-white matte" effect was called the Williams Process and it made famous John Fulton's film The Invisible Man (1933). To capture the footage of the Invisible Man undressing, actor Cloud Raines was dressed in a black velvet suit and filmed against a black background. .
The effect produced was so striking and memorable that this method was used in subsequent sequels to the film, even though more efficient processes became available over time.
Blue screen
The Williams Process had its drawbacks. For example, against a changing background, any shadows on the object were not taken into account. An alternative was invented by Dodge Dunning around 1925. It would later be called the Dunning Process.
Colored lighting was used in this process. The screen in the background was illuminated in blue, and the object in the foreground was illuminated in yellow. Using dyes and filters, blue and yellow could be separated from each other to create moving "matte". The Dunning Process was first used in King Kong in 1933.
The disadvantage of the Dunning Process was that it only worked on black and white film. Color film required a different technique. It was created by special effects artist Larry Butler. He demonstrated it in the film “The Thief of Baghdad” (1940). Butler shot the subject against a blue background on a Technicolor three-film camera. Blue was chosen because it is the least represented color in human skin. And blue film has the smallest “grain”.
By separating the blue film from three Technicolor negatives, Butler created a "matte" silhouette similar to Williams' Process. Then, using an optical printer, a relatively new invention at the time that combined different filmstrips into one, Butler first removed the blue background from the front plate, and, using a negative of the changing matte, removed the foreground space from the back plate. The last step was to connect the front and back plates.
This blue screen technique earned Lawrence Butler an Academy Award for Best Special Effects in 1940, but it also had its drawbacks.
Firstly, this process was time consuming, as it involved several steps with an optical printer. Secondly, a significant drawback was the presence of a blue border, almost always visible in the frame.
In addition, it did not take into account small details such as hair, smoke or motion blur.
But despite this, the Blue Screen process was actively used in such box-office films as “The Ten Commandments” in 1956.
"Yellow" chromakey
Hollywood continued to experiment with variations of the blue screen process, including ultraviolet matte, such as in The Old Man and the Sea.
But the real challenger to blue screen was created in the late 50s. And this was done by one of the giants in the world of composition - Petro Vlahos.
PETRO VLACHOS
In the mid-50s, Vlachos developed the "sodium process". This process was used extensively by Walt Disney Studios in the 60s and 70s. The process involved the actors standing in front of a white screen and being standardly lit. The screen itself was illuminated by powerful sodium lamps, similar to orange street lamps.
Sodium vapor produces light of an unusual wavelength - approximately 589.3 nanometers, and no longer. Using a specially coated prism inside an old Technicolor three-film camera, this wavelength of sodium light was separated. Then it was recorded on a special black and white film, automatically creating a moving black and white “matte”. The rest of the light was captured by standard Technicolor film, which is insensitive to yellow-orange sodium light.
This technique created the best moving “matte” of that time. It was first used by Disney in The Parent Trap and then in The Absent-Minded Professor in 1961. In 1964, the sodium process earned the film Mary Poppins an Academy Award for Best Special Effects.
This technique had only one drawback. There was only one sodium prism, so only one chamber in the world could perform this process. This camera belonged to Disney and they did not rent it for small amounts.
Revenge of the Blue Screen
In the late 50s, MGM was going to shoot Ben Hur in the MGM Camera 65 format (65 mm film). Then they turned to Petro Vlahos to help them with the composition. Vlahos
was the inventor of the sodium process.
They didn't want the problems that came with filming The Ten Commandments on a blue screen. But the sodium process could not be used since its prism was made for 35 mm. film, not 65mm.
So Vlahos was asked to do something to improve the blue screen process. After 6 months of difficult work, Vlahos made a discovery.
And here's where things get a little complicated...
Most colors that are not pure green or pure blue contain approximately equal amounts of blue and green.
Therefore, when creating the "matte" of the blue screen, Vlachos separated the green (or positive). He ran it under blue light along with the original color negative, exposing both pieces of film at the same time to create a "blue matte of difference." In this “matte” the blue and green colors matched.
Then, the blue positive was combined with the original negative and placed under red light. This made it possible to obtain a “front” “matte”. This "matte" was superimposed on the original separated colors. The exception was that the blue part was replaced by green with a green difference mask. Although, in essence, this was an artificial blue department.
This challenging process required 12 pieces of film to go from a master negative to a master internegative. But it was amazing because it solved the problems with edges and fine details that blue screen caused.
This process was so successful that it was actively used for almost 40 years. The creation of a microprocessor-based optical printer made it faster and more accurate. This printer was used by Richard Edlund in the movie The Empire Strikes Back. Next big change will be digital.
OPTICAL PRINTER IN “INDUSTRIAL LIGHT & MAGIC” FOR “THE EMPIRE STRIKES BACK”
Digital Green Screen Victory
I deliberately avoided the word " Chromakey" (Further " chromakey") all this time. The fact is that historically this term was applied only to video systems. Now it can be used without fear. In early video mixers, "keyer" was the name given to the mathematical process. It created a color range in the video signal and made it transparent. This is a very common effect that has been used to create special effects. For example, weather maps or almost all TV channel news studios.
Blue screen color still dominated, but green began to take over when digital film post-processing began in the late 90s.
Why green? Mainly because green screen is easier and cheaper to light than blue screen. Green appears brighter on electronic displays, it was good for picking up keys when filming outdoors (where blue could match the color of the sky) and bright green was much less common in actors' clothing than blue.
BAYER FILTER IS A MATRIX OF RED, GREEN AND BLUE PHOTO AREAS ON MANY MODERN DIGITAL CAMERAS.
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