The Clapperboard and its Language

The clapperboard, or slate, is one of the most iconic symbols in cinema, yet it presents a vague notion to those who don’t know its specific use in filmmaking. Beyond its very simple, recognizable appearance, lies a more complex system which is key in the filmmaking process – and still remains relevant to this day since its invention some time around the 1920s.

What is the clapperboard and what is it used for?

The clapperboard is a device of simple construction, consisting of a small board – that is nowadays made of translucent acrylic glass, but used to be made of slate, hence its alternative name – attached to a pair of clap sticks, usually made of wood. It is held in front of the camera before (sometimes after) every take and the sticks are clapped before the action unfolds.

These elements fulfil the two main uses of the clapperboard. On the board, information about the production and each take is written, so every shot is easily identifiable by the editor. The sticks are clapped with the purpose of being able to sync audio easily in post-production, as in a professional environment video and audio will be recorded separately.

Who uses it?

The person in charge of the clapperboard during a shooting is the 2nd Assistant Camera (2nd AC), as per its US denomination, or Clapper Loader, a name that tends to be used more frequently in the UK. The job description in regards to the clapperboard not only entails operating it, but also filling out camera sheets. As part of its operation, it’s necessary to understand what to write on each section of the clapperboard and know how and when to call out the right instructions.

What to write on it?

The clapperboard is divided in different sections as can be seen in the image below.

  • Production: Name of the production
  • Roll: Identifies each roll of film, tape or media card (depending on which format the production is being shot on) the camera is recording onto. If there are multiple cameras, you will need to label the primary camera as ‘A’ camera and the second as ‘B’ camera.  Your roll on A camera could be A004 while B camera will start back at 1 such as B001.
  • Scene: Identifies the scene being shot, normally the scene number according to the shot list. (Pro tip: skip the letters “I”, “O” and “S”, as they could be confused with the numbers “1”, “0”, and “5”.)
  • Take: Identifies each take – every time the camera records and stops is considered a new take, always starting at 1.
  • Director: Name of the Director – do not misspell!
  • Camera: Name of the Cinematographer – do not misspell! – depending on the production, sometimes the letter assigned to the camera that is being used in a particular moment on a multi-cam shoot.
  • Date: Shows the date of the shoot.
  • Day/Night: Shows whether it’s a day or night scene.
  • Int/Ext: Shows whether it’s an interior or exterior scene.
  • Mos/Sync: Mos should be circled when sound is not going to be recorded, conversely Sync should be circled when sound is being recorded.
  • Filter: Shows whether filters are being used on the lens.

For the day/night, int/ext, mos/sync, most AC’s will put a piece of tape over each element that isn’t in the shot.  For instance, if it is an INTERIOR scene, then put a piece of tape over the Ext mark on the slate.  If you have any doubt to what to put on the slate, reference the shooting script as the heading of each scene will label what scene number and whether it is int/ext.

How to operate it?

The 2nd AC would normally wait until the AD calls for slate. Then, walks into frame, positions the clapperboard where it can be clearly seen by the camera (or cameras), and calls out the instructions. Once the camera starts rolling, they call out “Mark!” and clap the sticks.

When calling out the instructions, it’s very important to be familiar with the difference between the UK and US slating system.

In the UK, every single shot has its own unique ‘slate number’ starting from 1, regardless of the scene.  A new shot can be defined when the position of the camera changes, the subject or focus of the camera changes (for instance on a different character), when a lens change occurs or when any other major change happens. Take this example: let’s assume the scene order of the day is Scene 14, 27 and 6. The system would go something like this:

Scene 14, Slate 1, Take 1

Scene 14, Slate 1, Take 2

(New setup)

Scene 14, Slate 2, Take 1 – whatever the setup doesn’t affect the slate number

(New scene)

Scene 27, Slate 3, Take 1 – whatever new scene doesn’t affect the slate number

(New scene after a few slates)

Scene 6, Slate 17… and so forth – the slate never resets.

In the US however, every new scene has its own number and then each new shot has a character, that goes the alphabet, with takes starting from 1. If the end of the alphabet is reached, the letters are doubled-up (AA, AB, AC, and so on). With the same scenes as the previous example, it would look something like this:

Scene 14A, Take 1

Scene 14A, Take 2

(New setup – e.g. from Close-up to Wide)

Scene 14B, Take 1

Scene 14B, Take 2

(New scene)

Scene 27A, Take 1

(After 28 new setups)

Scene 27AB, Take 1… and so on.

In the US system, it is common practice for a 2nd AC to use entire words when reading out the slate – either using the military alphabet or made-up words. For example: “Scene fourteen alpha, take 1!” or “Scene fourteen apple, take 1!” so there is no confusion.  It is even more common that you will not use the word ‘Scene’ when calling out the shot and may simplify it to “fourteen alpha, take 1” instead.

Useful terminology and situations

  • Soft Sticks

In a situation when the 2nd AC has to clap very close to talent, they would call out “Soft Sticks” instead of “Mark” not to distract the actors.

  • Second Sticks

If they clap incorrectly, they call out “Second Sticks” instead of “Mark”.

  • End slate/Tail clap

When for whatever reason it’s not possible to use the clapperboard at the beginning of a shot (for instance if the shot starts on a high crane and the slate is not possible to be close enough to the camera), this will be held upside down first, then rotated back to its normal upright position and clapped at the end of the shot.

 

  • MOS

This stands for “Motor Only Shot” and it means recording without sound. The clapperboard should be held with a finger or hand between the sticks or alternatively with your hand over them when they’re shut.

  • Pick Up

When another take occurs and the actions starts halfway through instead from the beginning, the take number increases but PU should be added to the number.

  • After False Start

If both sound and camera are rolling but the take is cut before action is called, AFS should be added to the number.

Tips

  • Keep the slate as still as possible when clapping the sticks. If you move during this action, you risk the sticks not being clearly visible at a particular frame to sync the sound.
  • When the 1st AD begins calling for turnover, already have the slate in frame and ready. You will waste time and/or film or memory by not being there.
  • Try to find out where the slate needs to be beforehand.  You can do this by referencing the monitor.
  • However, don’t just stand there with the slate in frame while the 1st is pulling focus for refence marks–you will get on their nerves very quickly as they cannot see through your slate!
  • You want the slate to fill as much of the frame as possible without it being too big.  The easiest way to determine the proper place is for every 10mm of the focal length of the lens you stand approximately one foot away from the lens.  If you are filming with a 50mm lens then you should stand 5 feet from the lens and the slate will be the proper size in frame.  Knowing distance and anticipating this will help serve you as you move up the chain to become a focus puller/1st AC. Even if you live outside the US and use the metric system, it is common that lenses will still use the imperial system for the witness marks (distance from the optical plane).
  • If you buy a labelmaker it makes it incredibly easy to label things that are consistent like the production name, director, cinematographer, etc.
  • Some 2nd AC’s use pre-written tape with numbers and letters to fill out other boxes like the scene and take and borrow these from the back of the clapperboard as needed.
  • In most instances the slate should be perfectly parallel to the lens, however there are instances when lights bounce off the slate and may reflect this back into the camera. Investigate this beforehand so you will be ready and not need to adjust.
  • Anticipate changes ahead of time. While the shot is being recorded, go ahead and *quietly* erase the previous take and write the next one there.  You will then be ready for the next take if it is needed.
  • It is a best practice to plan your route away from the camera before the 1st AD calls for turnover. You may have to tuck into a corner of the set that isn’t being used or find a way around obstacles.  If you mark the slate and then panic for how to get off set or disturb a piece of the set, you will look like an amatuer or you might make enemies of other departments. Further, you should stand on the side that you will exit—if you were to walk across the frame then this is time taken instead of shooting.

Juan Cruz is a cinematographer and editor based in London. He is about to graduate from the University of Greenwich in the MSc Film Production.
In his films, he likes exploring technology-related dystopias. He also loves comedy and playing drums.

Introduction to Motion Control: An IMIS event

Most of us remember the scene of Harry’s arrival at Hogwarts across the Great Lake with Hagrid, as the castle looms out at us from the darkness. Or have that legendary image in our minds of the Imperial Star Destroyer gliding ominously through deep space in Star Wars IV: A New Hope. But we also have most likely seen any of those commercials in which leaves of lettuce, slices of cheese and tomato and pieces of chicken fall exactly in place on top of a loaf of bread in slow motion. Funnily enough, all of these have something in common: they have been filmed using motion control.

What Is Motion Control?

The guys from Mark Roberts Motion Control, Peter Rush and Dorian Culmer, were there to tell us all about it. Motion control is a means to create difficult or “impossible” camera movements and special effects by accurately controlling the trajectory of the camera. Cameras are mounted onto robotic rigs controlled by a piece of software, and they’re able to move at very high speed with incredible precision. Therefore, the same movement can be repeated again and again, for example, to generate special and visual effects.

Although it seems like a pretty modern development, motion control actually started before digital times. Around the 80s, there was a very busy scene in London in particular, to create everything that wasn’t digital. As machines and skills improved in this area, they started filming models – which is how the previously mentioned Harry Potter and Star Wars scenes were made. Models were the main reasons for motion control; first they would film the model, and then they would integrate it with a background and other elements to create a scene.

London became the centre for commercials in the 80s and the 90s, with many big-time directors today, eventually moving on from commercials to film. A higher demand for fast machines surged, machines that could shoot a commercial in 1 or 2 days, or that could film 3 to 4 movements per day. This requirement was different of that in Hollywood, and it was Mark Roberts who started meeting this demand by creating these machines. The first one of the notably mobile machines was called “Cyclops”, which is still a company staple today, capable of filming 3 meters per second with great accuracy using high-end cameras such as the RED Dragon, flawlessly shooting in 6K.

Uses Of Motion Control

Motion control has countless uses, the main ones focussing on VFX creation and live action. Since the camera can follow exactly the same very precise path repeatedly, it is possible to get different layers (actors, background, foreground) that can be overlaid and matched together at the time of compositing. This can also be used to “clone” people, change foreground and background objects, for morphing – which is when one person transforms into another person or thing, a very popular use – or to put things together that couldn’t have possibly been filmed together.

Other uses within VFX include being capable of shooting a scene very accurately so that only one pass might be necessary in post – for example when the camera goes through a glass or an eyeball. It can also shoot forwards, backwards, change the scale (size of the movement) and the time of the movement. The latter is another very popular use, which is combined with compositing to create scaling shots – the most recent example is 2015’s Ant-Man. To create the main effect seen in the film, it is necessary to have exactly the same camera movement for the man and the background to later put them together, otherwise they wouldn’t match. Along the same lines, it is also possible to do scaling by taking footage that has been filmed without motion control, first by tracking the movement to create the initial camera path and then filming the foreground or background with the same path to put the scene together afterwards. Alongside with these, it is also widely used for VFX previsualisations.

Additional uses of motion control include high speed shots, with rigs that can film 4 metres per second (3 metres per second on tracks), which are popular with food commercials, since it can trigger other movements – this is how the ingredients fall on top of the bread. It is also utilised in animation – it is possible to create stop motion or go motion that have complex camera movements – in sports, such as the Olympic Games or Formula 1 and for space research.

Is Motion Control Necessary?

Sometimes it may seem that motion control is unnecessary. Why not fix it in post? Since the quality required in cinema features is an expensive and slow work path, it makes post-production for high resolution sequences also very expensive. It can also be very difficult when it comes to fixing incorrectly filmed VFX shots. Thus, it is normally more efficient to shoot correctly the first time using motion control rather than fixing it in post.

The one thing that motion control requires however, is lots of planning to be done properly. Therefore, the director usually gets together with the VFX Director and the DOP or Operator, and decides if it’s necessary, and if so, how to best work out the shots they need. The disadvantage is that most people aren’t actually aware or don’t know how long it takes to use motion control, or how much money they need to get it right properly. For this reason, if deciding to use motion control, it is best to get someone on board who is properly trained, knows the equipment required, how to use it and how long it will take. This way, the shoot will be properly planned and therefore the production will end up saving more by getting it properly done the first time, instead of wasting valuable resources such as time and money due to a wrong kit decision or last-minute changes.

Juan Cruz is a cinematographer and editor based in London. He is about to graduate from the University of Greenwich in the MSc Film Production.
In his films, he likes exploring technology-related dystopias. He also loves comedy and playing drums.