The gap between frames is the one measurement people guess at, and it is the one that decides whether an arrangement reads as a single composition or as several separate pictures that happen to share a wall. The answer is narrower than most people expect.
The number: 4 to 8 cm
For almost every arrangement, the gap between frames should be between 4 and 8 cm. Below 4 cm the frames crowd and their edges merge into a single dark grid. Above 8 cm they stop reading as a group, and the wall between them becomes a visible element rather than a background.
Within that range, scale the gap to the frames:
| Frame size | Gap | Reason |
|---|---|---|
| 21×30 and 30×42 | 4-5 cm | Small formats crowd easily but disperse faster |
| 50×70 | 5-6 cm | The standard case |
| 70×100 | 6-8 cm | Larger frames need more air to stay separate |
| Mixed sizes | 5 cm throughout | One constant gap; never vary it by neighbour |
Formats are listed in full in the poster size guide.
One gap, everywhere
The most common mistake is not choosing the wrong gap — it is using several. A wall with 5 cm between two frames and 7 cm between the next pair looks like a mistake even to someone who could not name what is wrong. Pick one number and hold it across the whole arrangement, horizontally and vertically.
This applies even when the frames differ. A 30×42 next to a 70×100 gets the same 5 cm as any other pair on that wall.
Peacock by Ohara Koson japansk kunstposter
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Gap is measured frame to frame
Measure between the outer edges of the frames, not between the printed images. Mount width varies between formats, so spacing by the image leaves the frames unevenly spread — which is what the eye actually sees.
If you use mounts, the mount is part of the frame for this purpose. What a mount is and when it earns its place is covered in the passepartout guide.
The gap changes with viewing distance
A hallway seen from a metre away needs tighter spacing than a living room wall seen from four metres, because at close range gaps look larger than they measure. In a corridor, go to the bottom of the range — 4 cm even on 50×70. On a large wall seen from across the room, the top of the range keeps the arrangement from collapsing into a single block.
Lay it out on the floor first
Put the frames on the floor in the arrangement you intend, set the gaps with a ruler, then measure the total span before anything goes on the wall. That total is what has to fit the furniture below — two thirds of the sofa or bed.
Marking the wall in pencil before drilling is worth the two minutes. Mark the position of the hanging hardware, not the top of the frame — on most frames the hook sits 5 to 10 cm below the top edge, and forgetting that is how an arrangement ends up hanging lower than planned.
Twelve arrangements with the gaps already calculated, and the total dimensions for each, are in the gallery wall guide. Frames in every size are here, and the height the whole arrangement should centre on is in how high to hang art.