Hasta La Motion!

V. Paint

Paint. When do you paint frames as opposed to roto? How can you decide which method will work best given the task at hand? One thing to always remember, is that painting multiple frames to remove something is time-consuming and wasteful. There are always easier ways to get rid of a camera, or a grip, or wires. By using roto you can effectively get rid of the aforementioned items, and use your paint skills to clean up harder areas of the frame. Paint is also not only used for clean-up, but also for creation. You can use paint strokes as lightning strikes, for electrical surges, for laser blasts. Almost anything that is dynamic in action can be created by paint. During my time on Stargate SG-1, I painted items such as staff blasts, zat hits, and electrical surges.

A method I’ve seen by some beginning artists (I’ve done this as well when I started!) is to paint tracking markers out by hand. Every frame. Or paint out wires. Many wires. Things to look out for when analyzing a frame and deciding when to paint come with practice and time. Let’s say I want to remove a wire rig that’s holding up an actor. And for the sake of argument, it’s a simple rig on a simple background. An actor suspended on bluescreen. The easiest way to remove this wire is to copy a bit of the surrounding bluescreen over the wire. You’re not painting through it, you’re covering it up with other bits of the frame. You’ll have to track this little bit and cover the wire as it moves, but it’s vastly easier than painting a clean frame and trying to match it up via grain later. However sometimes it becomes necessary to do that. Pretty soon the only areas you will need to paint and touch up are where the wires meet the body.

Marker removal is tricky business. It can also be known as wire removal, grip removal, prop removal, etc. The object of doing marker removal is just that, removing a marker from an object, background or person for the comp. This could involve removing LEDs from a tracking shot, removing dots from an actors face, or removing wires and props from scenes when they shouldn’t belong. The method most often used to remove tracking markers is replacing them with a similar background of the environment. If the tracking markers are on greenscreen, you would replace the markers with parts of the greenscreen, or similar color green.

How do you replace the markers with bits of the background or foreground now comes into question. I touched upon this briefly in the Paint section. However, instead of painting a clean frame, you can use roto and mask around the offending tracking marker. By offsetting your background and using the roto to effectively cut a small swatch of background (or foreground), you can cover up the marker! Often times you’ll use tracking markers only to track roto to cover the marker up. This method can usually be used for static markers such as the ones on greenscreens and tracking markers in environments.

For more elaborate cover ups, other techniques combined with the one above will usually get you in the right ballpark. For wire removal, instead of a circle of roto, you will have to create a line of roto over the wire, and instead of tracking, you may have to manually animate the roto to cover the wire. Large roto is usually not the best. The cleanest way is to cover the wire with a sliver of roto, and have a nice feathered edge. This should give you a smooth transition from the background over the wire. You may need to approach wire removal in sections instead of as a whole. This would involve many different techniques, from using the background as a cover, to painting a clean frame of a certain section of background and regraining it to match and positioning that in place. Ideally you would use painting frame by frame as a last resort, and then only as a way to touch up edges or spots you may have missed. Prop removal usually requires either painting out a clean frame of an image, or having a clean background plate without the prop in it. While the methodology is here to start a decent clean up, it takes a little time to sometimes accomplish a good wire and/or rig removal. Tracking marker removal is much easier!