Technical notes · 8 notes · S1–S3
Technical notes
Eight notes on what decides a wall before the quote: pixel pitch and viewing distance, cabinet grid against opening size, power and heat, brightness on a sun-facing wall, category selection, service access, and two misreadings that change the specification.
S1 Parameters · Notes 001–004
The rule is one metre of viewing distance per millimetre of pitch, and it holds for most rooms. It fails for text content, for sun-facing walls, and for any project where the audience never stands where the drawing says they will.
A wall is not cut to the opening. It is assembled from cabinets, and every cabinet is a whole number of modules. Get the module size wrong and the wall finishes short.
Two numbers on the spec sheet decide three things on site: the breaker, the cable and the air conditioning. They are not the same number, and quoting the wrong one is how rooms overheat.
Brightness on a datasheet is measured in a dark room. A wall facing the sun is judged against whatever light is falling on the glass. The second number is never on the sheet, and it is the one that decides.
S2 Selection · Notes 005–006
The category is not a marketing label. It sets six parameters before anyone argues about price, and getting the category wrong is the one mistake that cannot be fixed on site.
Service access is decided by the wall the panel is fixed to, not by the panel. On a corridor wall there is no rear, and a rear-access cabinet is a permanent maintenance problem bought at a discount.
S3 Misconceptions · Notes 007–008
A brighter wall does not read better in a room that is already bright. What changes is the black level, the glare and the electricity bill. Readability is a ratio, and only one side of it is on the datasheet.
Pitch is a distance requirement with a price attached. Past the point where the eye stops resolving pixels, a finer pitch changes the invoice and nothing else.