Movie Making Manual/Effects/Human Cloning
Human cloning is a special technique used within a film to give the impression that there are two characters possibly communicating with each other. This technique has been used in many films and TV shows and Vloggers (Video Bloggers) commonly use this technique because it is reasonably easy to accomplish.
There are three main techniques to accomplish cloning within a film which are listed from hardest to easiest, these include:
- Split Screen
- Split Screen with Motion
- Body Doubles
- Editing Tricks
The process of using split screen is one of the most common techniques used and is extremely effective because the actor appears more than once in the frame.
Originally the scene has to be set out to accommodate the effect. It is extremely advisable to avoid using moving objects in the background like trees as they can make the effect extremely difficult to perfect.
Once the scene is blocked, place the camera on a tripod or on a flat surface so it won't move. To avoid excessive colour correction or motion tracking, the exposure to manual and do not touch the camera during the shoot. It is extremely advisable to have a stand in to read lines so the timing between the two sets of dialogue is similar to improve the overall fluency of the shot.
Now it's time to shoot. Shoot your actors first set of dialogue, then the other, remembering not to touch or move the camera. It is easier to have your actor stand on either side of the frame during each take, taking care not to cross an imaginary centre line. If the actor crosses the line (no pun intended) or crosses the actor, it will mean more work for you and you may have to rotoscope which is long and arduous.
Once you have to two pieces of footage, take them into your VFX or NLE software that has a masking tool. From here, line up your two clips so that the talking lines up, you may need to clean the audio up by removing the stand in's dialogue.
From here, create a mask around the actor on the top layer. The second layer should show through and hopefully line up correctly. Some colour correction may be needed to fix any colour errors.
- Extremely effective
- Relatively easy to set up
- Accomplishable with one person
- May be tedious to accomplish
- Small Margin of Error
- Takes the longest.
- Set up your shot.
- Set up your camera on a steady surface.
- Shoot your action using a stand in for better timing.
- Take your footage into your effects software.
- Clean up any audio and create mask.
- Apply Colour Correction.
- Do NOT touch or move the camera (Discussed later)
- Set a Manual Exposure to avoid excessive colour correction
- Try to avoid crossing the line or the clone
- Turn off any Image Stabilisation.
Split Screen with Motion
Split Screen with Motion is virtually the same process as just standard split screen but there is an added challenge, movement. Movement is a challenge because it means the clips won't line up correctly, so a few techniques can be applied to fix these issues.
- Motion Control Rig
- Motion Tracking
- Handheld Motion added in Post
Motion control is when a camera movement is able to be exactly replicated. Motion control is often used in shots in effect shots that need to align exactly or shots that are just too intricate to be completed manually. Motion control rigs are generally expensive and require specialists to program in movements and to make sure the rig functions correctly. This means the clips can be exactly lined up and although rotoscoping may still be needed, it will be less intensive.
In simple pan, tilt and roll movements (camera does not physically move), motion tracking and stabilization may be a viable option. Using After Effects as an example, if one track is stabilized, the other piece of footage can tracked with the data applied to a null object. The stabilised track can be parented to this null and it will appear to "stick" to footage, from here, you character can be masked out and you have the same result as a standard split screen. This technique is useful when a tripod isn't readily available, however this is a much more tedious approach and should only be used as a last resort. If you do not understand the guide above, check out this guide by simonsaysfx for a tutorial.
The third option is to add a digital handheld shake in post. The process from the standard split screen guide must be used and the footage can be parented to handheld shake data or a plugin may be used. Motion in a shot can give a certain sense of realism, but it is generally harder to accomplish.
Body Doubles are a common method of cloning as they can also be used in the same shot. Body doubles are generally the same height, body build and have the same hair style/colour. Note that a wig can be worn to correct any hair issues. A body double's face is almost never used unless they are a twin and look exactly alike, so they are used in "over the shoulder" shots. It is advisable to use quicker edits as critics may notice small imperfections in an image.
Body doubles are one of the most common methods of cloning in larger productions because it doesn't take as long to shoot or edit, however the major issue is finding the actual double. In major films, a stunt person is usually hired and can be used in this instance.
- Should look alike from behind. They should have the same;
- Hair Style/Colour
- Used in OTS or shots where their face isn't used.
- Faster edits are advised
- Used in larger productions.
Editing tricks can be used to give the impression that there are two of your actors. Although there are a few ways to pull of this effect, only two will be explained. The first is just shooting your scene normally, using your actor in the reverse angle. Using L-cuts are a way to help improve the believability of your scene.
The other method is to pan quickly between the two clones, the most effective way to do this is to complete one set of dialogue and pan quickly to the direction of your clone. Then you set up the next shot and pan quickly towards it for your actor to deliver their line. You should have two shots:
- Action -> Pan away
- Pan to -> Action
Line these two clips up and during the two pans, add a cross fade to blend the clips. You should have;
- Action -> Pan <CROSS FADE> Pan -> Action
Don't forget you can play with the timing to give the impression that the clone is standing close or far away. A colour correction is also advised to make sure the two shots match.