Backdrops and Green Screens
published 7th March 2024 I TECH TERMS,
INDUSTRY KNOWLEDGE
One of the core questions you’ll need to answer when designing and drawing a set is what can be seen beyond its physical barriers.
Any opening, be it a window, a door, a balcony or an entire background that serves as an extension to your physical set will bring up two questions:
- What can be seen beyond the opening?
- How can it be achieved?
In this post we’ll dive into the options for the second question, examining backdrops, green screens and LED volumes. We’ll look at the advantages and disadvantages as well as the key decision factors such as cost, script and screen value.
Let’s start with the options available to create a world beyond the physical set:
Let's start with the options available to create a world beyond the physical set:
1. Set dressing covering the opening (curtains, drapes) + black out
Probably the easiest and most cost effective way to deal with smaller openings if the exterior world is not very important to the overall story. It can be easily done for smaller windows at the back of a set. Shutters, curtains and set dressing on and in front of the windows will help to disguise the fact that the exterior world isn’t shown.
2. White out/ back lighting
is equally cost effective as the black out option, but will require more discussion with director and DOP for bigger openings because it has a strong impact on the look of the film. Stained, frosted and patterned window panes can be helpful in distracting from the non existing exterior.
3. Painted backdrop
Scenic (=painted) backdrops are used more often than one might think in contemporary productions. One thing to consider is that painted backdrops will always have a more painterly and theatrical feel than its printed alternatives. This might influence the overall visual style of the film. It’s an artistic choice as much as it is a technical.
4. Printed backdrop, also called Translites (stock or custom made; front-lit, back-lit or both)
The options for the printed backdrop vary with regard to material (vinyl, cotton weave) and whether they are front-/backlit or both.
There are special versions that can be used for day and night time scenes. The usually higher production costs for these day and night softdrops need to be justified by a higher screen value which is usually the case for long standing key sets of a production (i.e. main office seen frequently over the course of several seasons).
The suppliers of printed backdrops have a catalogue of existing backdrops as well as stock photography that can be turned into a backdrop.
They also offer the service of shooting a new location based on the requirements of the script and can therefore be used to link interior scenes on a studio set with exterior scenes shot on location.
5. Projection
Projection and gobos are usually used in addition to printed backdrops to simulate a moving sun or moon. In some cases projections are used on larger surfaces in place of LED screens. Most of the time this happens for cost reasons. One important thing to consider is that the projector is a light source that will influence the surrounding environment and can make it difficult to light the set.
6. Green or Blue Screens
Green or blue screen are in essence placeholders for backgrounds that will be inserted in post production by the VFX department. The specific green or blue tone makes it easier to identify and replace the surfaces after filming.
It’s important to understand what will be seen in place of the green screen and have a general idea of the virtual geography around your set. You also might want to talk to your VFX counterpart about edges and transitions, i.e. irregular organic shapes if your set is a rock face that will be extended in post.
Additional factors to consider is the use of reflective surfaces on set and the overall distance required between set and green screen. Both will influence the amount of green pollution that needs to be removed in post production.
7. LED Volumes/ Virtual Production
Huge semi circular LED screens (= volumes) are used to create entire sets in a process generally referred to as virtual production. It’s quite costly as it requires specific equipment and crew. What is seen on the LED screen needs to be designed and created in form of virtual assets. It needs to be run and lit in a game engine and synchronised with the tracked camera movements. It’s mostly used for monumental landscapes as they can be seen in The Mandalorian.
Another less complex version of this technology that makes use of stock footage is used to create the exteriors for driving car scenes.
All these options will have different costs, lead times and processes associated with them. Depending on your script, budget and the visual style of the production you will prefer some of them while others will be unsuitable or not affordable.
The following are core questions you’ll need to consider in making your choice:
- What are the requirements of the script and story? What role does the background play in telling the overall story?
- What’s the overall visual style of the production?
- How often (number of scenes and pages) and how close will the back ground be seen? Is there a change in times of day or seasons?
- How big is the opening or background? How much of it (in terms of surface area) will we actually see?
- Is this background shown at other points in the story or does it need to link to a location?
- What is the budget?
- What is the time frame considering lead times for the different options?
- Are there many reflective surfaces or paints used on the physical set? How severe would green pollution be?
- How much space is available behind the opening?
Answering these questions should put you in a good position to discuss the options with your designer and supervisor. It’s a good idea to involve VFX, camera and the gaffer in this discussion as well.
I hope this post was helpful in giving you a better understanding of the options you have when it comes to creating the exterior, non-physical part of your set.
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