Chroma key has become a familiar part of video production, from home blogs to professional film studios, and it can also be useful for photographers. Let’s figure out together what a chroma key is and how to choose the right one if you don’t have one yet.
How chromakey works
Green background, or chromakey, is a very popular tool in modern photography and videography. The idea of using chromakey is simple: you shoot a person or other object against a green background, transfer the image to your computer and use software to replace the green background with…yes, anything!
Here your possibilities are limited only by your imagination: from coniferous forest to a spaceship, from the Eiffel Tower to Sauron’s tower. The trick is that green is almost non-existent in human skin tones, so this color is easy to cut out in post-processing and replace with the background you need. This is why chroma key is so loved by both Hollywood directors and Youtube bloggers.
Green or blue chromakey — is there a difference
Blue is also minimally represented in human skin tones, which is why it has become a popular alternative to green backgrounds. The difference between them is small. Blue backgrounds have an advantage for dark and night scenes due to their lower brightness. On the other hand, it may require more powerful lighting.
In general, in order not to be mistaken, choose the classic green chroma key or combined options with blue and green on different sides, for example Raylab RF-12. This is a folding muslin chroma key measuring 150 by 200 cm (we will talk about all these characteristics in more detail below). It is suitable for both vlogging in the home studio and outdoor portrait photography. Also, a quick-folding background is a super option for tiktokers: it takes up little space and is easy to take with you everywhere.
What matters when choosing a chromakey
An intuitive rule applies here — the larger the object you are shooting, the larger the background should be. Most often, chroma key is used to photograph people, but how to calculate the right size? For a “sitting” video blog or a waist-length portrait, a background 1.5–2 meters wide will suffice. The height is unprincipled — any standard chromakey will do, for example Fujimi FJ 706GB-180/210. For full-length shots, the width increases to 2.7–3 meters, and the height is selected individually — depending on the height of the model and how much of the floor will be in the frame.
The Raylab BC01 3m x 6m Muslin Chroma Key is just right for full-length shots. The fabric has no seams and joints, so it will be easy to “cut out” the object.
For video filming in motion or a photo of two people in full growth, you need a background from 5 meters wide and 4 meters high.
Naturally, if you are going to shoot a large group of people or larger objects (like a car), you need even larger options.
Are you going to use chroma key for location shooting? Then a folding background will be the most convenient option. The Raylab RL-BC06 measures 1.5 meters by 2 meters, suitable for shooting children or waist-length video. Although with due skill it is possible to adapt this background to the full height of an adult. Also RL-BC06 will be good for product photography. This background can be set to a working vertical position in 10 seconds, without the need for additional stands and crossbars.
This option is also well suited for a small home studio — when folded, it takes up almost no space.
For a large studio, you can choose larger stationary options such as GreenBean Field 3.0 x 7.0 (note that the mounting system is purchased separately).
Usually chromakeys are made of fabric, paper or non-woven fabric (more often it is matte vinyl or spandex). Fabric chromakeys are mainly sewn from muslin, a dense cotton fabric, and photophones are also made from it. Such chromakeys are good for their unpretentiousness and durability. With fabric, you can drape a wall or furniture so you don’t have to use additional fastening systems. The main disadvantage is that fabric chromakeys wrinkle easily, which causes shadows that are more difficult to remove during post-processing.
Paper backdrops are sleek and inexpensive, and can be rolled generously to cover the floor, but they’re not suitable for drapery, and you can’t take one out. Thus, paper chromakey is a good option for photo studios (including home ones), and thanks to the length of the background, you can shoot large objects. 11 meters of paper background Raylab 010 Green will cost less than four thousand rubles, a fabric background for the same money will be no longer than 6 meters. In addition, the paper background is much lighter. But paper has a big minus — it gets dirty very easily (after all, they will stand on it with their feet). Therefore, you will either have to change the chroma key periodically, or spend much more time in post-processing (and end up changing it anyway).
Non-woven backgrounds cope with this problem — they are easy to clean and are not inferior in strength to muslin ones. Also, such backgrounds crumple a little, which simplifies the work with the image. Of the minuses of non-woven backgrounds, small perforation can be noted — usually it is not visible (especially on video), but it can appear in side lighting if the object is too close (for example, in product photography).
The Raylab RL-BC06 mentioned above is made of spandex — high reflectivity and the absence of seams can be written down as definite pluses of this chroma key.
Chroma key opens up huge creative possibilities for photographers, videographers and vloggers. You can quickly find the right background without much effort during post-processing.
When choosing a chromakey, you should pay attention to the size of the subject (the larger it is, the larger the width and height of the background should be), the material (convenient, but with its limitations — non-woven background; cheap, but short-lived — paper; conditional golden mean — fabric background ) and decide whether you will take the background for location shooting (then you should stop at the folding option).