The three pitches side by side
P1.5, P2 and P2.5 sit next to each other in most indoor ranges, and the numbers are close enough that the choice looks minor. It is not. The pitch sets how many emitters go into a square metre, and that count moves faster than the pitch does. From 2.5 mm to 1.5625 mm the pitch falls by about 0.94 mm, while the pixel count per square metre rises from 160,000 to 409,600.
Three other figures travel with the pitch: the physical module size, the number of pixels on each module, and the lamp package. Module size gets the least attention and is usually the one that decides whether a wall fits the opening it was drawn for.
What a fixed wall delivers at each pitch
Take a 4,000 mm by 2,250 mm opening, a size that covers most boardrooms, control rooms and lobby feature walls. Divide each dimension by the pitch and the resolution follows directly.
At 1.5625 mm the wall resolves 2,560 by 1,440. At 2 mm it resolves 2,000 by 1,125. At 2.5 mm it resolves 1,600 by 900. That last figure is the one worth stopping on: 1,600 by 900 sits below 1080p, so a 4 m wall built at 2.5 mm cannot carry 1080p content at native resolution.
Turned around, the same arithmetic gives a minimum width. Native 1080p needs 3,000 mm of width at 1.5625 mm, 3,840 mm at 2 mm and 4,800 mm at 2.5 mm. Native 4K needs 6,000 mm, 7,680 mm and 9,600 mm. When both the opening and the content resolution are fixed, the pitch is already decided.
Module size decides whether the wall fits
The modules are not the same physical size across the three pitches. The 1.5625 mm module is 200 by 150 mm carrying 128 by 96 pixels. The 2 mm module is 128 by 128 mm carrying 64 by 64. The 2.5 mm module is 160 by 160 mm carrying 64 by 64.
Apply those to the same opening. At 1.5625 mm it takes 20 modules across and 15 down, and the wall lands exactly on 4,000 by 2,250 mm. At 2.5 mm it takes 25 across and 14 down: the width is exact at 4,000 mm and the height finishes 10 mm short at 2,240 mm. At 2 mm neither dimension divides evenly, so 31 or 32 modules across gives 3,968 or 4,096 mm, and 17 or 18 down gives 2,176 or 2,304 mm.
There is nothing wrong with the 2 mm module. It means the opening has to absorb a remainder, and that remainder is normally taken up by a trim border or by moving the structural opening. Settling it on paper is cheaper than settling it after the steel is in.
Where the cost difference comes from
No price figure belongs on a page like this, but the driver behind the difference is not a mystery. Cost tracks the number of emitters, and the emitter count is the density. One square metre at 1.5625 mm carries 2.56 times the emitters of the same square metre at 2.5 mm, and 1.64 times the count at 2 mm.
Driving and processing follow the same curve. More pixels per square metre means more driver channels, more data moving into the wall and more processing to fill it. Ask what the control system has to carry at the chosen pitch, because that answer changes between these three even though the cabinet looks the same from the front.
The consequence is easy to miss when comparing quotes: the step from 2.5 mm to 2 mm buys less than the step from 2 mm to 1.5625 mm in emitter terms, yet both are presented as one step down in pitch.
Match the pitch to the smallest thing on screen
Viewing distance gets most of the attention and it matters, but the harder test is the smallest detail the content has to render. Measure that detail on screen in millimetres, then divide by the pitch.
A 20 mm capital letter, roughly the smallest comfortable size for a wall read from a few metres, is 12.8 pixels tall at 1.5625 mm, 10 pixels at 2 mm and 8 pixels at 2.5 mm. Below about ten pixels of height, letterforms start to lose their shape, so dense text, data tables and maps push the choice finer much earlier than video does.
This is why two projects with the same viewing distance can land on different pitches. A lobby running large motion graphics reads perfectly well at 2.5 mm. The same lobby running a live operations table does not.
What stays the same across all three
Three things do not separate these pitches, and knowing them in advance saves time when quotes are being compared.
Scan rate is 1/32 on all three, so duty cycle and the brightness headroom that follows from it are not a differentiator here. Power is quoted at 400 W/m² average and 800 W/m² peak on all three, so the electrical supply and the heat load do not change with the pitch. Brightness sits in the same band: the 1.5625 mm and 2 mm modules are quoted at 700 to 1,000 cd/m², and the 2.5 mm module at 1,000 cd/m² and above.
That leaves four things worth deciding on: the resolution you can reach in the opening, whether the module grid fits it, how much detail the content carries, and what the emitter count does to the budget. Everything else is secondary.
A wall that could not show 1080p
A 4 m wall was specified at 2.5 mm for budget reasons. The resolution landed at 1,600 by 900, below 1080p, so the client's native content was always upscaled. Moving to 2 mm reached 2,000 by 1,125 and a clean fit, at a higher but expected emitter cost.
Two rooms, two pitches
Two lobbies of the same size took different pitches. One ran large looping video and read well at 2.5 mm; the other ran a live operations table where fine text needed 1.5625 mm. Same distance, different content, different answer.
A practical sequence for p1.5 vs p2 vs p2.5
- Fix the opening before the pitch Measure the width and height you actually have and note the smallest detail the content carries. The opening and the content decide the pitch before any catalogue comparison does.
- Divide the width by each pitch Resolution follows directly from the opening. A 4,000 mm by 2,250 mm wall resolves 2,560 by 1,440 at 1.5625 mm, 2,000 by 1,125 at 2 mm and 1,600 by 900 at 2.5 mm, so only the finer two carry 1080p natively.
- Check the module grid against the opening Each pitch uses a different module size and pixel grid, so the wall may not divide evenly. Settle any remainder as a trim border or a revised structural opening on paper, before the steel is ordered.
- Match pitch to content detail, not just distance Dense text, data tables and maps push the choice finer than video does. A 20 mm letter is about 8 pixels tall at 2.5 mm and starts to lose its shape, so a lobby running an operations table needs a finer pitch than one running motion graphics.
Frequent errors in p1.5 vs p2 vs p2.5
“A smaller pixel pitch is always the better choice.” — It is better only when the opening is wide enough to use the resolution and the content carries detail worth it. On a narrow wall or with large video, a finer pitch buys pixels no one resolves and adds emitter cost.
“Pitches that look close cost about the same.” — Cost follows emitter count, which moves with the square of the pitch change. Going from 2.5 mm to 1.5625 mm makes the pitch about 1.6 times finer but puts 2.56 times the emitters into each square metre.