Congratulations, you’ve made it: Your dreams of joining a film production have finally materialized, you’re now stepping on a set, and the director is about to call “action.” And then someone arrives and clicks a board.
Since the start of filmmaking over a century ago, there has been a need to organize and know what shot is being filmed at any point. That is where the clapperboard comes in.
Clapperboards are used to identify which scene and take a crew is shooting at any particular time, as well as where audio and visuals sync up during postproduction.
Also known as film slates (or just slates), clapperboards are actually composed of two parts. The main part, the slate—named so because they literally used to be a piece of slate—has all of the identifying information about that specific scene, which helps editors properly select and place footage in the timeline. Attached to the top of the slate is a clapper stick; the “clack” sound it makes causes a sharp spike on the audio track, which the postproduction team matches to the video frame of the stick closing.
Clapperboards come in all shapes and sizes, but almost all film slates will feature these three sections:
The roll or reel number
This area of the board used to refer to the roll of film you were shooting on. In the digital era, it signals the specific media file that the recording will be saved on to. Use a three-digit numeral to signify the roll number, as well as a letter to signal which camera it is recorded on (if there are several), like so: A001, followed by A002, etc. For audio, use a letter further down the alphabet, such as W001.
The scene number
This is the scene in the script being recorded. Both letters and numbers are used to indicate not only the scene, but also the shot. Any time you switch setups—for example, the camera moves, the angle changes, or the lens is swapped—it counts as a new shot. For the first shot of the scene, you just mark the number. From there, you go up from the letter “A.” For example, the first setup of scene 35 would just be marked “35,” the second setup would be “35A,” the third setup “35B,” until all shots are completed.
The take number
To indicate which take you’re on of a specific shot, simply count up from 1 until the direct is happy with the shot.
So, for example: If you’re using your “A” camera’s fifth digital media card to capture the sixth take of the second setup in scene 15. The slate would read:
- Roll: A005
- Scene: 15A
- Take: 6
Collectively, these three fields are known as the "Head ID," the most basic function of the clapper. If yours has more spaces than these, it is likely to also cover the following:
- Production title: the title of the production
- Director: the name of the director
- DP: the name of the director of photography
- Camera: either the name of the camera operator or a letter assigned to each camera when necessary
- Date: the current date of the shoot
- FPS: the frame rate used for the shoot (often 24fps, but at times it can be something else)
- Int/Ext/Day/Nite: used to indicate whether the scene takes place indoors or outdoors, during the day or at night
During production, all of the information on the clapperboard is primarily for the script supervisor, who keeps detailed notes on the production that will be used during postproduction. Whenever possible, check in with the script supervisor while marking the slate.
The second assistant camera—also known as 2AC or clapper/loader—is the crew member in charge of working the clapperboard. To get into position to call the slate, stand where the camera operator tells you to with the slate in focus. (If it’s a close-up shot, be mindful of how close the slate will be to the actor’s face.) Before you can clap the sticks together, a few things will happen:
- The first assistant director will “call the roll” by first asking for quiet on the set, announcing “picture’s up,” then saying “roll sound, roll camera.”
- The sound recordist responds “sound speed,” confirming sound is good to go.
- The camera operator responds “camera speed,” confirming the camera is good to go.
Now it’s time to slate. Hold the clapperboard firmly in front of you and call out the scene and take numbers. Because certain letters sound similar, be sure to use the phonetic alphabet; “scene 15 alpha, take six,” for example. Then, shout “mark!” and clap the sticks together.
That’s it! The clapperboard is filled up, the camera is in position, and the director is about to call “action!”
On most large-scale productions with a full crew hierarchy, you’re still likely to see a clapperboard (although it’ll probably be a whiteboard these days). When it comes to high-budget sets, you might even run into a “smart slate,” which includes a digital time code synced to the camera’s time code.
However, filling out a film slate for each take is time-consuming. If you’re working with a small, low-budget crew—or a crew of one, where you’re editing your own footage—it can be practical to simply clap your hands in front of the camera to synchronize sound. Plus, many modern digital cameras provide metadata and file names to help keep track of what you’re shooting. Many modern-day video editing software options have features to help sync audio and video, such as the “merge” tool in Adobe Premiere or free options such as Filmora.
Of course, technology will never be perfect—these options are great if you’re working on a time crunch or with a skeleton crew, but there will always be value in finding any way to make it easier to manually sync audio and visuals.