Video wall color evenness: check every screen in the grid

Open the tool on each screen. A screen might have its own computer, one computer might drive several screens, or a window can sit on each monitor, and any of those can join the same session. Create the session on one of them, then join from the rest by typing the 4-character code or opening the share link. Put each screen in full screen mode. The controls hide behind the small toggle in the bottom left corner, so open them there when you need to change the color. Start with the mid gray that's the page color, then go to white, then a dark gray, then a saturated red, green and blue.

Look for a screen that's warmer or cooler than its neighbors, a brightness step between two screens that sit side by side, and patchiness inside one screen. Patchiness means uneven color or brightness across a single screen's own area, and the gray uniformity check explains how to judge it. Walk back a few steps and look at the whole wall, because small differences show up more easily when the screens sit edge to edge. If you find a mismatch, match each screen's settings first, such as brightness, picture mode and color temperature, then run the colors again.

The tool doesn't measure any screen, and it can't adjust one for you. It sends each screen the same color values, but how a screen shows them depends on that screen and its settings. Matching is therefore a judgment by eye, and the tool can't tell you which screen is right. A wall that needs real matching, such as in retail or a control room, calls for a hardware colorimeter (also called a calibrator or spectrophotometer) with its software to measure each screen, plus each screen's own calibration tools to adjust them.