Gradated gray or color reference strip — shoot at head or tail of every setup for post-production calibration. Ensures consistent grading across all takes.
You're shooting a scene, the sun is moving, the lights are drifting — and later in the grade, you ask yourself: Was it really that green, or is that just the monitor? That's exactly where the color wedge comes in. A piece of plastic or paper with defined gray tones and color references that you hold in front of the camera at the beginning and end of each take. Not sexy, not dramatic, but absolutely critical for digital post-production.
The classic version — a gray scale with neutral tones from white to black — serves for exposure calibration. The colorist or grader looks at the material, identifies the known gray tones, and can deduce how the camera actually captured the scene. This sounds simple, but it's essential: Without this reference, you're flying blind. You don't know if a skin tone looks natural or if the entire shot just has a color cast. On long shooting days, with multiple cameras, or for critical commercial grading, this becomes a daily routine — documenting every setup, every lighting change anew.
Professional sets work with extended color wedges — not just gray, but also colored fields (red, green, blue, magenta, cyan, yellow). Some use the GretagMacbeth ColorChecker or similar industry standards. This allows you to perform an automatic white balance in the grade with color correction software or to precisely synchronize color spaces. Especially in digital cinema — where you don't have physical film storing the exposure — this is your only bridge between set and post.
In practice: Right at the beginning, when the lights are set and the first take is running, hold the wedge in front of the camera for one or two seconds — not too quickly, the camera needs time to react to the coloration. After that, you can start. Some teams also shoot it at the end to document lighting changes. Digitally, it costs nothing — one or two frames that are later cut out or remain for the colorist at the editing suite. Analog, on film, this was a bigger consideration because every meter of celluloid cost money. Today: no reason not to do it. It's unprofessional to forgo it.