TV & STUDIO SUPPLIES
Professional green screen & blue screen sets from Gerriets
Perfectly equipped for studio purposes: with Gerriets' specialized products for green screen/blue screen applications, you can achieve first-class results in front of the camera. Whether custom-made for your purpose, temporary or permanently installed - we offer the complete package.
"Many factors play a role in the successful presentation of die-cut sets. Room size, lighting and the motif itself influence the result. The choice of keyable material is crucial. The keyers available today do have certain tolerance corridors. But even they can't save poorly set up green screens/blue screens."
Birger Bustorff (from 1997-2019 light-setting 1st cameraman at SWR)
Tips and parameters for successful studio recordings
This text explains the basic concepts of the green screen or blue screen technique, also known as greenbox or bluebox. The "chroma keying" process enables the cropping of image content - known from weather forecasting, for example. It was first used in the 1940 film The Thief of Baghdad.
Green screen / blue screen technique
In this technique, a subject is photographed against a monochrome background, usually green or blue. These colors are particularly suitable as they are rarely found in skin tones. Green has the additional advantage that cameras can capture it more accurately because their sensors contain twice as many green pixels as red or blue.
Other rare colors such as mint or pink would also be possible, but are uncommon. Alternatively, a subject can also be cropped using strong differences in brightness - for example with a strongly illuminated background and a less well-lit person. The process itself is called "keying", the subsequent combination with a background is called "punching".
Illumination
Uniform lighting is crucial for a good result. The subject and background should be lit separately to avoid shadows and light reflections. Even if keying programs can compensate for slight fluctuations in brightness, clean lighting is the best prerequisite.
Lighting system / spotlights
Soft, flat illumination avoids harsh shadows and strong contrasts. Depending on the set, different types of lamps may be required, such as asymmetrical spotlights for the background.
Color location
The chromaticity coordinates describe the RGB components of a color in the range from 0 to 255. 0/177/64 is often used for green screens and 8/39/245 for blue screens. These values can be set directly on the light mixer for LED rear projections. Other colors such as mint or pink can also be used as long as the keyer recognizes them correctly.
Cove
A cove is the gentle transition from the floor to the wall that prevents distracting edges in the image. It can be made of bent wood, filler or textiles. For temporary studios, a continuous textile that runs from the background to the floor is often sufficient.
Luminance - homogeneity
Unevenness, folds or material differences in the background make cropping difficult. Smooth surfaces can be achieved with the TELESTRETCH system, for example, which is attached to structures. Shadows should also be avoided as they impair the keying.
Spill
Spill refers to distracting light reflections that spill from a green background onto clothing or hair, for example. Hair is particularly susceptible as it is often semi-transparent. This can be remedied by using black fabric to cover areas of the green screen that are not required.
Room size
Sufficient distance between the person and the background is important. If the distance is too small, shadows or spill effects are more likely to occur. In small studios, a track system such as TRUMPF 95 can provide more flexibility.
Reflection behavior
Matt, low-reflective surfaces are ideal as they do not reflect light back into the camera. Materials such as STAGE MOLTON are well suited, but usually have to be illuminated separately. TELEVISION CS is easy to clean, but can be prone to reflections in unfavorable lighting.
