How To Use A Clapperboard The Right Way

INTRODUCTION

This little piece of equipment is perhaps the most iconic symbol in filmmaking, but it also has a number of pretty important practical purposes.  

Since I actually used to work as a 2nd AC or loader for a number of years, it was my job to use this little guy on set. 

So I thought I’d track down my old slate and provide a bit of an explainer as to what the purpose of it is, what all the information on the board means and go through the ins and outs of the real ways that a slate is used on an industry level set.

WHAT IS A SLATE?

The slate, sticks, or clapperboard are all names for this piece of translucent acrylic attached to a pair of wooden sticks that can go clap.

It has two main uses on a film set: synchronising the sound with the video footage and conveying information. 

While broadcast, documentary or solo shooters may have a mic that records both sound and video footage as one single file, on an industry film set the footage is recorded on a cinema camera, while the sound is recorded separately on a mixer by a dedicated sound recordist.

A slate uses both a visual cue, the action of the sticks coming together, and an audio cue, the sound of the clap, as a reference marker for synchronising them together. Practically this means that editors can find the moment that the sticks collide, and the moment that the clap is heard, and use that as a starting point for both clips.

Now the video and the sound are in sync.

The second use of a slate is to give the editor information. All of the numbers, letters or even symbols that are written on the acrylic section of the slate in a black whiteboard marker are a way of passing on information to the editor.

Each shot in a movie has a unique series of numbers that identifies it, and places it within the order of the story. Properly labelling each take and having a system to find them is important because there may be hundreds or even thousands of different takes on a production. 

Slate information allows the editor to both know which scene in the screenplay the shot fits into and gives each shot a label so that it can be talked about and identified by the editor, as well as correspond to any notes from the script supervisor or camera report. 

On top of this, the 2nd AC may write additional information on the board, such as to notify the editor that VFX work is intended to be added to the shot or to convey the camera settings that were used. 

There are two types of slates that can be used: a smart slate which has a timecode running on it, and a regular, old clapper board or dummy slate which can only use a clap to sync the sound. The timecode on a smart slate can be synchronised with both the camera and the audio mixer. 

How this works is that the audio recording device will have a kind of digital clock that outputs an exact time in hours, minutes, seconds and frames - called timecode. The sound person will then ‘jam’ the timecode by connecting a timecode cable between the audio recorder and the smart slate. This sets the timecode on the slate to be exactly the same - frame perfectly - as the time on the audio recorder. The same is then done to the cinema camera so that all devices are running the same timecode as the audio recorder.

This means that every time the smart slate is opened on camera it displays a running timecode that can be synchronised perfectly to the same timecode as the audio recorder - thus syncing the footage - with the physical clap being a backup way of syncing the sound.  

SLATE INFORMATION

When a screenplay is written, each scene will be given a number. The first scene is 1, the second scene is 2, etc. However, during the process of shooting, scripts are almost never shot chronologically. 

So, to avoid confusion and to stay on top of what scene is being shot and when, it is labelled on the board with a scene number. 

When the editor gets the footage they can then group all of the shots with the same scene number into the same bin.

Next we’ll move onto the slate. Most scenes that are shot will use multiple camera angles and lenses to cover the action. Every time that the camera moves onto a new shot size, angle, or switches a lens this is called a new slate, or slating up.

There are two systems for representing this: the US system and the UK system. The US system is probably the most common and uses letters to represent a slate.

For example, the first board for the wide shot on scene 26 will just say 26, with no letter. When the camera moves onto the second shot, a close up, the board will slate up to 26A, then when a third shot is filmed, the board will slate up again to 26B.

When speaking about slates we use the NATO phonetic alphabet: 26 alfa, 26 bravo, 26 charlie. Although sometimes 2nd ACs can also come up with creative names that start with the first letter of the slate.

You also usually skip the letters I and O, so that they aren’t confused for a one and a zero. 

If shooting a VFX shot, this can either be written on the board or a V can be added before the scene number. The same can be done with an X to show that this was shot by a second unit, or with an R to indicate a scene that is being reshot. Different productions and different script supervisors may also use different letters or methods for communicating these cases. 

The UK system uses numbers instead of letters. So the first shot of the production will be slate one, the next shot will be slate two, and this slate count keeps going up with each new shot setup or lens change until the production ends. 

This means that you don’t always have to announce the scene number, only the slate number - although the scene number will usually also be written on the board. 

Then, for each slate setup, usually multiple takes will also be recorded. This starts at one for the first take and keeps going up. Then when you change to a new slate you start over with take one again. So, an example of a typical board may read 26A, take three.

At the front we also have the roll number. This comprises a letter followed by a series of numbers. Each letter represents what camera shot this footage. If there is only one camera it will be called A cam. This letter goes up for every extra camera that is used. So if it’s a multicam shoot with one main camera, one Steadicam camera, and one action camera, the main camera will be A cam, the steadicam will be B cam, and the action camera will be C cam.

Then each card that goes into this camera, shoots and gets transferred to hard drive will be labelled with a series of numbers. So the first card shot by A cam will be A001, or the 112th card shot by B cam will be B112. If shooting on film, the same principle applies to each new roll of film that is used. So the 8th roll of film shot by A cam will be A008.

All of this information about the roll number, scene, slate and take will be recorded by the script supervisor along with any extra notes, such as what takes are good, what lenses were used for each shot, or what takes may have had lapses in continuity. 

The board is also labelled with fixed information like the production company, title of the production, director’s name, cinematographer’s name and the date. Because this information doesn’t change much, it is usually either done using a printed label from a label maker, or handwritten with a permanent marker on tape.  

HOW TO USE A SLATE?

When 2nd ACs do a slate they need to be as quick and as accurate as possible. 

If you put the board into shot too early, it will block the framing and view of the camera operator. If you leave the board in shot too long while the camera is rolling then you are wasting valuable card recording time or film stock that is running through the camera.

What 2nd ACs do is carefully listen to the instructions of the 1st assistant director.

They will call ‘roll sound’, to which the sound recordist will press the red button and say ‘sound speed’. The instruction ‘roll sound’ is a good cue that it’s time for the 2nd AC to insert the board into the frame. 

This gives the 1st AC a moment to pull the focus to the board so that it is sharp and can be read by the editor. Next the AD will say ‘roll camera’. 

Once the 1st AC is ready they will press record on the camera and say ‘speed’ or ‘rolling’. Because the board is already in frame and sharply in focus when the camera rolls it means that the first frame that the editor will see for each take will be the slate. This helps the editor immediately identify the shot number without needing to search through the takes for it.

Once the 2nd AC hears the focus puller say ‘speed’ they can announce the board. If using the US system this means saying the scene and slate letter followed by the take: for example, ‘26 bravo take three’. 

The focus puller’s I’ve worked for like to then say ‘mark’ or ‘mark it’ to confirm the camera is rolling, the board is sharp and it can be clapped. Then as soon as they’ve clapped the board, the 2nd will get out of the shot and duck for cover as quickly as possible.

Running through the whole process, it’ll sound like this: 

‘Roll sound.’

‘Sound speed’

‘Roll camera’

‘Rolling’

‘26 alfa take three’

‘Mark’

*clap*

In most cases you want the clap to be quite loud so that it is clearly picked up by the boom and lapel microphones, but not to be deafening. Loaders also modify the strength of the clap depending on how close it is to the actors. 

If shooting a tight close up and the board needs to be right in front of the actor’s face, it’s best to notify the boom operator ahead of rolling that you’ll do a soft clap. They will then get the mic close to the board and you can do a nice gentle clap in front of the actor’s face that doesn’t put them off. 

For tight shots, some loaders carry a cute little insert slate which is small enough to be fully read in a close up.

If they fumble the clap or it is too soft to be picked up, the 2nd AC will then loudly announce ‘second clap’ and hit it again.

When positioning the slate in frame, you want it to be as readable as possible - not too small and far away or too large and close to the camera. The rule of thumb when shooting with a Super35 sensor is that the focal length of the lens should be equivalent to how many feet away from the camera the slate is. So, if using a 50mm lens, the board should be 5 feet away. If using a 100mm lens the board should be 10 feet away.

If shooting with anamorphic lenses or with large format cameras that have a wider field of view, the board can be placed a bit closer to the camera than this rule. Good loaders are able to place the board in frame without looking at a monitor based on knowing the focal length of the lens alone.      

There are three different sound variations that can be done, all of which are signified a different way with the clapper board. The most common is sync sound, where the sound recorded is intended to be synchronised with the recorded footage. To convey sync sound, the clapperboard must always enter the shot with the sticks open, showing the editor that it’s meant to be clapped. 

This is often incorrectly done in pop culture references where the board starts closed, then opens in shot and claps.

Wild sound means that sound will be recorded for the take, however this sound does not have to be synchronised with the footage. This is sometimes done when recording ambient noise or sound effects.

Loaders will write ‘wild’ on the board and this time either enter the frame with the board closed, or with their fingers holding the board between the sticks - this will allow the timecode on a smart slate to run, but indicates that the board will not be clapped.  

Then there is MOS - which signifies that no sound will be rolled on this take. Again, a big MOS will be written on the board and the board will enter and exit frame closed - without a clap. 

If multiple takes in a row will be done within a single roll of a take then the loader may write ‘series’ or put an arrow next to the take.

Next we have the end board. This is where either the 2nd AC is not quick enough to fetch their board and complete a front slate after ‘roll sound’ has been called, or if no board has been requested up front, such as if working with animals or children that may be spooked by a loud clap. 

In this case, after ‘roll sound’ is announced, the 2nd AC will say ‘end board’ loudly at the beginning of the take. The scene will then play out in full. Just as ‘cut’ is called to end the take, the 2nd AC needs to quickly and loudly again announce ‘end board’. They will then quickly put the board in front of the camera with the sticks open, but in an upside down position, they will announce the board, ‘26 alfa take three, end board’, give it a clap, then spin the board so that the editor can read it. 

Putting a board in upside down means that the board signifies whatever was previously shot. For example, if no slate was done on a take, then the board can be placed in frame upside down with the sticks closed, a new clip can be rolled, then the board is spun to the correct orientation. This signifies that this board is the label for the previous take.

If shooting with multiple cameras that can all be synced with one board, then the roll number of each camera should be written on the slate, such as A008 and B007. In this case the loader will say ‘alfa, bravo common mark’ before clapping.

If multiple cameras are being used and there is a 2nd AC for each camera, then each loader will announce their camera, in alphabetical order before clapping. For example, ‘26 apple take three alfa mark’, ‘bravo mark’.  

Finally, if a director decides that they only want to record a small portion of the scene, such as a specific line, then P/U will be added next to the take which stands for pick up. This will be announced as ‘26 alfa take three pick up’.