Test the Wall Before You Pay for It: A Half-Day LED Volume Test With the ASC's Free StEM3

An LED volume can look perfect to the eye and still photograph wrong, and stage reps are not going to point that out. Since July there has been a free, standard set of test material for exactly this problem. Our view: if you are paying for a volume day, spend half a day on a test with the ASC's StEM3 kit first. Don't book on the strength of a showreel.

What StEM3 actually is

StEM3 (Standard Evaluation Material 3) comes from the ASC's Motion Imaging Technology Council. The ASC announced it on 20 July 2026, and the files are hosted on the Academy Software Foundation's Digital Production Example Library. It costs nothing. Each asset has its own licence, published on the library site. Michael Goi ASC, co-chair of MITC, explained why it exists: on early volumes "color rendition was off, dynamic range was sketchy", so the council wanted material that sets out how a stage is supposed to look.

The DPEL listing contains:

• Six Unreal Engine scenes: Cybercity (18.0 GiB, UE 5.4), Forest (17.6 GiB, UE 5.1), Base Camp (5.4 GiB), Subway Station (2.8 GiB, UE 5.3), Back Alley (13.9 GiB, UE 5.3) and Saloon (24.5 GiB).
• 2D material: an LA driving plate (8.4 GiB), a lightning plate, and a 25-stop exposure chart as an EXR.
• A reference short, Warped: Cybercity, written by Goi and Jay Holben and directed by Holben, in SDR (5.4 GiB) and HDR (38.0 GiB), plus a behind-the-scenes film.

According to fxguide's write-up, the kit is designed to show up problems with colour consistency across panels, saturated colours and subtle colour separation, deep shadows and highlights, seams, moire and scan artefacts, panel sync, tracking stability, how content responds to exposure, shutter and the colour pipeline, and interactive light on actors and sets. Supporters include Amazon Studios, Dolby, Epic Games, Sony, Walt Disney Studios, ROE Visual and Pixomondo.

One thing the kit does not include is a procedure. The DPEL page tells you what the assets are for, not how to run a test day. The protocol below is ours.

Before the test day

• Send the stage the asset list a week ahead. The scenes were built across UE 5.1 to 5.4. Ask the stage to confirm, in writing, that every scene opens and runs at frame rate in their build. A stage that can't load a free standard package in a week has told you how your own content will be handled.
• Bring your own camera package: the body, lenses and frame rate you plan to shoot with, and your monitoring LUT. A test shot on the stage's house camera only shows you their camera.
• Agree on the processor settings before you start, and get the stage to change them between setups if needed. Brompton's on-camera guidance recommends dimming the wall at the processor, not in the content, so you keep bit depth and avoid banding.

The half-day protocol

1. Exposure chart (45 minutes). Put the 25-stop EXR on the wall and frame it so it fills the shot. On a waveform, count how many steps the camera can separate before the blacks merge and the highlights clip. Repeat at the wall brightness you will actually shoot at. If shadow steps break into bands at low brightness, the processor is short on bit depth at that level.
2. Colour and seams (45 minutes). Load a saturated scene such as Cybercity at night and do a slow pan across several panels. Then shoot from 30 to 40 degrees off-axis. Look for panels or batches that shift hue, and for cabinet edges you can see in flat areas of colour. Use a vectorscope here, not your eyes.
3. Shutter and sync (30 minutes). Shoot at your intended frame rate and shutter angle, then at the odd settings a director will ask for on the day: 50 or 60 fps, a narrow shutter for action. Rolling bars or scan lines mean a sync or refresh problem. Find it now, not with talent on the floor.
4. Moire walk (20 minutes). With your longest planned lens, pull focus step by step from the actors' mark towards the wall and note the distance at which moire first appears. That distance is the real limit for blocking. Rules of thumb don't agree: one rental house's technical guide gives both "pixel pitch in mm times 10 equals safe distance in feet" and "one metre per millimetre of pitch". For a 1.5 mm wall that is about 15 feet in one case and about 5 feet in the other. Measure it with your own lens.
5. Tracking (45 minutes). Use Back Alley or the Subway Station with a strong foreground parallax line. Do fast pans, a push-in and a handheld move. Watch the join between practical set and wall for swimming or lag. A short delay that you only notice on whip pans is acceptable if your boards don't include whip pans. Make that decision deliberately.
6. Driving plate and interactive light (45 minutes). Put a person in a car buck against the LA plate, then use the lightning plate. Check skin tones on the monitor against a reference shot under conventional light. The wall works as a light source, so check how it reads on skin as well as how it looks behind the actor.

Failures that should end the booking

Some problems can be fixed by the stage. Others mean you should walk away. This is how we would sort them:

• Walk away: colour shift between panel batches that you can see in a pan; scan artefacts at your planned frame rate and shutter that the stage can't remove during the test; tracking lag on moves that are actually in your shot list.
• Negotiate: moire nearer than your planned blocking (change lenses, focus or staging, or ask for a different stage area); banding at low brightness (ask for processor-side dimming); slow scene loading (make the stage load your content the day before the shoot).
• Accept and note: small off-axis colour shift outside your planned camera angles; mild clipping on the extreme top stops of the chart if your content never goes that bright.

The printable checklist

• Stage has confirmed in writing that all six StEM3 scenes run at frame rate.
• Your camera, lenses, frame rate, shutter and LUT are on site.
• Exposure chart shot at shooting brightness; usable stops recorded.
• Pan and off-axis colour checked on a vectorscope.
• Every planned frame rate and shutter angle shot and reviewed at 100%.
• Moire distance measured with your longest lens and written on the floor plan.
• Tracking checked on the most aggressive move in your boards.
• Skin under the wall's light compared against a reference.
• Results filed with the stage, so any fix they promise has a baseline to be checked against.

Half a day of stage time is not free, and some stages will want to charge for it. Pay it. It costs much less than learning about any of these failures on the first day of the shoot.