We do a lot of special effects here at Tools! , and sometimes it seems like it’s just 1-2-3-Software! We’ve all seen the “click to remove” behind the scenes videos from DVD extras. But it’s rarely that easy. Usually, there’s a few steps between “green” and “clean” that take a skilled fx person–like us–to make perfect. Here’s the 5 steps we take to turn our fake into a piece of cake. (Err, sorry for all the puns).
Full Process (Aka, Click-n-Go)
Here’s the full process covered in one video. A shot like this probably take about 3-6 hours for a talented fx person.
01 Shoot the Footage
The key to shooting the footage is to make sure the green is lit as evenly as possible. The more even the color/shade, the easier it is for the software to do its job. We make sure we know all our shots ahead of time with storyboards so we know how each shot needs to look. The last thing we have to be careful of is clothing choices. White clothing will pick up and reflect the green–making some of the actor disappear as well. Light colors like yellow can also cause problems. You may have noticed the bottom left corner, we can get those out later–just watch.
02 “Garbage” Mask
A “garbage” just means a rough trim of the edges of the footage. We can make the software work better if we give it less to process. We roughly “cut” the edges with a vector mask and animate it to follow the actor. This process can take a couple minutes to a couple hours, depending on how much movement there is.
03 Rough Clean
NOW we use the filters our software comes with. There actually thousands of shades of green in our greenscreen. The software can only take out so many of them depending on how high we set the “tolerance”. The problem is that it might also start to take away other light colors–skin, teeth, eyes–if we set the tolerance too high. In this stage, we’re looking for 85-95% of the green removed, while still leaving all the of the actor on the screen. If you look in the bottom left hand corner, you can see some speckles of the screen left behind. This is fine for now.
04 Fine Cleaning
Now we mask specific parts of the actor and just user filters on these specific areas. Really fine areas like the rapidly moving hands will have to be masked manually. That means we draw a mask around the hand almost every frame to carve them out while retaining details like the fingers and motion blur. No little speckles should remain in around the figure.
05 Color Correction
Depending on your background, you might need to color correct or shade the actor to match the background. When we’re filming, we try to match light direction and temperature, but since we need a flatly lit background, we can’t do too much. This will require putting filters and animated filters on top of the actor to get them to be the same color/lighting as the background. Luckily for us, this project just required the actor to be in a big white space. We did warm up her skin tone a little to make her more lively though.
06 Final With Background
Here’s the final image with background. We did fuzz her edges just a little bit more to make her blend with the background. We also added her shadow onto the “i” of the logo if you look closely. Those little details can really make the actor seem like they’re in the space and interacting with the elements around them.
Did anyone catch the local commercial green screen joke in Bob’s Burgers? It’s only during the credit where they screen the family-centric commercial. Linda Belcher has a speckly green halo around her for some shots–indicative of a bad (home made) green screen job. That level of detail for a gag over the credits is pretty nice.