Removing the green “spill” from actors and props is a tedious yet indispensable part of compositing when working with a green screen. Not any more when using a virtual set, though. This solution not only simplifies post-production, but also makes work on the set considerably easier.
Unavoidably, the new technology also poses new challenges and requires very specific preparations. We experienced this first-hand when working on a commercial for the Air Wick brand, where the LED screens were used to transport the protagonist from her apartment to a fascinating world filled with fantastic plants and creatures.
The director wanted the animated vegetation we had created to be displayed on the set. Yes sir! Althought our models were quite complex as they had been created for the purposes of post-production, while the virtual set requires some optimisation of the objects during pre-production so they can be displayed smoothly in real time. It takes some special manipulations to make the models and animations on the LED screens appear more detailed than they actually are. Consequently, some of the animations had to be eventually removed or reduced.
In addition, the way a given material reacted to light proved to be exceedingly difficult to reproduce on the LED screens, which was especially true of transparent objects. It took us a number of attempts before we found the result satisfying. One rule to remember here is that objects viewed in high-performance 3D software will not look the same on LED screens.
Some of the differences will only be noticeable on camera or at the post-production stage. In the case of our commercial, it turned out that the camera would register more colours than the LED screens were displaying. In consequence, when we got down to colour grading during post-production, the foreground looked better than the background generated in the virtual set. It is, therefore, crucial to make sure that the image displayed on the LED screens has a sufficiently broad colour range.
Faced with all these difficulties, why did we not opt for the classic green screen? The major advantage of the virtual set is that the camera preview allows us to see each frame in its nearly final version. Certain details can, obviously, still be altered in post-production, but the overall composition of the background, which determines the framing and the camera work, is already there, visible in real time.
The director of the Air Wick commercial was able to change or scale the furniture visible in the room, freely search for the best angle and the so-called “look”, while a green screen would have forced him to rely heavily on his imagination with no guarantee of what the final effect would be.
All in all, it was a valuable lesson for everyone in the film crew and the result leaves nothing to be desired.