Poster sizes, and the margin a frame is going to eat
A poster shows every flaw and a frame hides the outer edge. How to pick a size, what margin to leave, and why paper is less forgiving than fabric.
Paper is the least forgiving thing to print on. Fabric absorbs ink and hides a little softness; paper shows the file exactly as it is, at reading distance, in good light.
Resolution matters more here
A design that looks acceptable on a shirt at 150 DPI looks visibly soft as a poster, because nothing is hiding it and people stand closer. Aim for the full resolution at the printed size rather than the minimum.
The frame takes the edge
Most frames overlap the print by a few millimetres on every side, and mounts take considerably more. Anything important within about half an inch of the edge is at risk of being covered.
- Keep text well inside the edge
- Backgrounds and colour fields can run to the edge safely
- Do not put a thin border right at the edge, because a frame that covers it unevenly looks like a printing fault
Choosing between the sizes
| Size | Suits | Watch for |
|---|---|---|
| 18 by 24 in | A wall above a desk | Detail at arm's length |
| 24 by 36 in | A feature wall | Needs a genuinely large file |
The editor shows the real print rectangle for the size you picked, and the file it produces is that rectangle at full resolution.
Portrait or landscape
Decide this before designing rather than after. Rotating a finished layout almost never works, because the eye reads the two orientations differently and the balance that felt right vertically collapses horizontally.
Paper shows compression
A photograph that has been sent through a messaging app has usually been compressed twice, and the artefacts that are invisible on a phone screen are clearly visible at poster size. Use the original file from the camera rather than the copy that came back from a chat.
Where it will hang
Decide the wall before the size. A poster that is too small for the space it is in looks like a mistake that cannot be corrected afterwards, and 24 by 36 is a great deal larger in a room than it looks on a screen.