title: Signage and posters (large-format print) applies_to: [print, signage, poster, large-format] version: 1.0.0 last_updated: 2026-05 stability: stable
Signage and posters¶
Large-format print: posters, banners, billboards, in-store signage, trade-show booths. Read print-fundamentals.md first.
The two key differences from small-format print:
- Reading distance — posters are read from 1-3m, billboards from 10-50m+. Type sizing is dramatically different.
- Resolution requirements — drop to 100-150 DPI at full size for most large prints (your eye averages at distance).
Sizes¶
Posters¶
| Korean / international | Size (mm) | Use |
|---|---|---|
| A4 | 210 × 297 | In-house / café notice |
| A3 | 297 × 420 | Café / store window |
| B3 | 364 × 515 | Subway poster |
| A2 | 420 × 594 | Movie / event poster |
| A1 | 594 × 841 | Conference / large event |
| A0 | 841 × 1189 | Trade show / hero poster |
| B2 | 515 × 728 | Bus stop, subway |
| B1 | 728 × 1030 | Subway platform |
| Subway 12-sheet | 3050 × 1525 | Subway corridor |
Banners (vinyl / fabric)¶
| Use | Size |
|---|---|
| Roll-up banner (현수막) | 850 × 2000mm typical |
| Pull-up retractable | 800 × 2000mm |
| Outdoor vinyl banner | 1m × 3m up to 5m × 20m |
| Trade show backdrop | 3m × 2.5m typical |
| Window vinyl | Custom to window |
Billboards / 옥외광고¶
Korean OOH (out-of-home) regulations specify approved sizes per location. Check with the OOH vendor for spec sheets.
Reading distance and type size¶
The "viewing distance × 1cm = letter height" rule:
| Distance | Min letter height |
|---|---|
| 1m (close-up poster) | 1cm = ~28pt |
| 3m (standard poster from across room) | 3cm = ~85pt |
| 10m (across street poster, large signage) | 10cm = ~283pt |
| 30m (billboard from car) | 30cm = ~850pt |
| 50m+ (highway billboard) | 50cm+ |
Real-world: large posters in subway stations need 80pt+ for headlines, 24pt+ for body.
Korean 한글 reads slightly larger than Latin at same point size due to character density. You can usually go 1-2pt smaller for Korean than Latin and stay legible.
Composition rules¶
One message¶
A poster is read in 1-2 seconds. One headline. One image. Optional one detail (date/place/QR).
┌─────────────────────┐
│ │
│ [HEADLINE] │ ← read in 1 second
│ │
│ [Image] │ ← supports headline
│ │
│ Date | Place │ ← detail layer
│ │
│ [QR] [Logo] │ ← signature
└─────────────────────┘
Don't pack a poster with paragraphs. People walk past.
Hierarchy¶
| Layer | Size | Content |
|---|---|---|
| Hero | 60-80% of poster height | Image OR headline |
| Headline | 10-20% | What this is |
| Detail | 5-10% | When / where |
| Signature | 3-5% | Logo, QR, attribution |
Visual weight¶
Posters work because of strong figure-ground contrast: - Big shape on contrasting background. - Bold type cutting through. - Clear focal point — the eye lands somewhere specific.
Avoid: - Even visual weight across the whole poster (no focal point). - 5+ images of equal size. - Tiny type covering 50% of the canvas.
Resolution rules for large format¶
The "your eye averages at distance" effect means lower DPI is acceptable as size scales up:
| Print size | Reading distance | Recommended DPI at print size |
|---|---|---|
| A4 poster (close hand) | 30cm | 300 DPI |
| A3 poster (close wall) | 1m | 200 DPI |
| A2 poster (room wall) | 1-2m | 150 DPI |
| A1 / A0 poster | 2-3m | 100-150 DPI |
| Subway poster | 1-3m | 100-150 DPI |
| Billboard | 10m+ | 30-72 DPI |
| Highway billboard | 30m+ | 15-30 DPI |
Don't waste resolution. A 300 DPI billboard at 30m is invisible to the viewer and costs 100× more in file size and processing.
Color and contrast for outdoor / large-format¶
Outdoor environments + distance reduce perceived contrast:
- Higher contrast than digital screen — black on yellow, white on red, etc.
- Avoid subtle gradients at large size — banding becomes visible.
- Brand colors may need adjustment — the bright red of a logo may print muddy at billboard scale; ask the printer for a press proof.
- UV stability — outdoor prints fade. Specify UV-resistant ink + lamination for any print exposed to sun.
Korean subway / outdoor regulations sometimes restrict color for safety (e.g., no flashing red near traffic). Check OOH vendor's compliance sheet.
Materials¶
Paper posters¶
- Standard offset poster: 150-200gsm coated paper.
- Premium poster: 300gsm matte cover stock (photo prints, sold posters).
- Window cling: PVC vinyl, removable.
Banners¶
- Vinyl banner: weatherproof, durable, 13oz / 18oz weights.
- Mesh banner: wind-permeable; for windy outdoor use.
- Fabric banner: premium look; trade show backdrops.
Signage¶
- Foamboard / KT 보드: lightweight, indoor.
- Acrylic / 아크릴: premium, indoor.
- Aluminum / 알루미늄 컴퍼지트: durable, outdoor.
- Vinyl on coroplast: cheap, election-sign quality.
Material affects perceived brand. A laser-print poster on copy paper signals "temporary / cheap." A fabric trade-show backdrop with grommets signals "premium / professional."
Subway / outdoor print requirements (Korean)¶
Korean subway poster specs (most common): - Size: B3 (364 × 515mm) or B2 (515 × 728mm) - Bleed: 5mm all sides - Resolution: 200-300 DPI - File: PDF/X-1a CMYK - Submit deadline: 7-14 days before posting
Each subway operator (Seoul Metro, KORAIL, Busan Metro) has their own spec sheet. Ask for the latest.
Korean billboard / OOH: - Specs vary by vendor and location. - Many have safety-content review (no offensive content, certain industries restricted). - Lead time: 2-4 weeks for production + posting.
Trade show booths¶
For 3m × 2.5m backdrops: - Headline at human-eye-level (1.5-1.7m from floor). - Logo at top OR centered above headline. - Don't put critical content below 0.5m or above 2.2m (people block view; eye height varies). - Tile-friendly design (some booths have visible tile seams every 1m).
Posters for subways: special considerations¶
Korean subway riders look at posters at 1-2m for 5-30 seconds (waiting for train). This is more reading time than a billboard.
You can include: - A clear headline. - One supporting fact OR image. - A QR code (people scan with phone while waiting). - Brand signature.
Don't include: - Long body copy paragraphs. - More than one CTA. - Tiny type at the bottom (lost on most viewers).
Production checklist (large format)¶
- Color mode: CMYK
- Resolution at print size: per category above
- Bleed: 5mm minimum (more for very large pieces)
- Safe area: 10mm+ inside trim for text
- Material specified (paper / vinyl / fabric)
- Finish specified (matte / glossy / lamination / UV-coated)
- File format: PDF/X-1a or PDF/X-4
- Fonts outlined or embedded
- Sample test print at 1:1 corner section if going to billboard scale (catch resolution / color issues)
- OOH compliance check (if outdoor / public space)
- Lead time confirmed with vendor
Common large-format mistakes¶
- Tiny type — minimum legible size at distance is bigger than designers expect.
- Wasted resolution — 300 DPI on a billboard is overkill.
- Center-aligned everything — gets lost. Pick anchor positions.
- Photography upscaled too far — pixelation visible at large size.
- Brand color shifts — RGB-bright color → CMYK-muddy. Test on press.
- Forgot bleed — subway posters cropped, white edges.
- Logo in corner so small nobody reads it — if branded, brand it.
Don't¶
- Don't design a poster like a brochure. Brochures have time. Posters have seconds.
- Don't put paragraphs of body copy on a poster nobody will stop to read.
- Don't ship 300 DPI files for a 4m × 6m billboard. Wasteful, slow.
- Don't ignore reading distance when sizing type. Test by stepping back.
- Don't choose vinyl banner material for a long-term sign. UV degradation.
- Don't skip sample proof for billboards. Color shift at scale is real.
Cross-reference¶
knowledge/print/print-fundamentals.md— CMYK, bleed, DPIknowledge/print/brochures-and-flyers.md— small formatknowledge/print/korean-print-conventions.md— KR specificsknowledge/typography/type-scale-fundamentals.md— type sizingknowledge/illustration/hero-illustrations.md— hero illustration use