Motion tests
A moving black-and-white grid that shows the rainbow effect on single-chip DLP projectors.
Line width
Lines
Cell size
Rhythm, jumps per second
Dot size
How to use it
Show this page on the projector from a PC or media player, full screen, at native resolution. Watch the moving lines, and let your eyes dart across the screen too. A single-chip DLP shows the colours one after another, so a white line can split into red, green and blue. The faster it moves, the wider the split. A projector with a faster colour sequence (an anti-RBE mode, for example) shows less of it at the same speed.
Line colour
White is the main test: a white line is lit in every colour field, so it gives the strongest rainbow. Coloured lines are only for diagnostics. In a pure RGB mode, pure red, green and blue should show no rainbow, because each one is lit only in its own field; at most a line can double in its own colour if that field repeats within the frame. If they show a clear one, the mode is mixing colours (adding cyan and yellow fields, for example). A faint rainbow is possible even in a pure RGB mode if the projector blends in other colours to hit the Rec.709 gamut. Yellow, cyan and magenta split into their two components.
Scenes and settings
The scene menu under the picture has three patterns. Grid: moving lines. In Settings you can set the line width (Auto or 1 to 16 px) and keep only the vertical or only the horizontal lines. Checkerboard: a moving field of black and white cells, with the cell size in Settings. Jumping dot: still white objects on black (a subtitle and a few bright shapes) and a dot that jumps between the corners and the centre in a steady rhythm. Follow the dot with your eyes: the rainbow shows up on the still objects while your eyes move. The jumps are always the same, so your eyes make the same movements on every projector and they can be compared. The Speed presets set the rhythm, from 1 jump per second at 1x to 6 at 16x; the dot size is in Settings.
The speed is in pixels of the actual screen per second: 1x is 120 px/s, 2x to 16x are multiples of it. The picture moves by the same whole number of pixels on every refresh, so the motion stays even. The line under the picture shows the resulting speed, the step times the refresh rate. Settings are saved on this device.
Mouse: click the grid to pause, double-click for fullscreen. Keys: arrows change the direction, + and − the speed, M switches the scene, space pauses, F goes fullscreen.
