title: Print fundamentals (CMYK, bleed, trim, DPI, paper) applies_to: [print, physical, production, prepress] version: 1.0.0 last_updated: 2026-05 stability: stable
Print fundamentals¶
Designing for print is not designing for screen. The math is different (CMYK not RGB), the resolution is different (300 DPI not 72/96 PPI), and you can't undo a print run.
This file is the foundation. Read before stationery.md, brochures-and-flyers.md, signage-and-posters.md, packaging.md, or korean-print-conventions.md.
Color: CMYK vs RGB vs Spot¶
| RGB | CMYK | Spot (Pantone) | |
|---|---|---|---|
| What | Additive (light) | Subtractive (ink) | Pre-mixed ink |
| Where | Screens | Most printers | Premium print runs |
| Range | Wide gamut | Narrower (~70% of RGB) | Specific colors only |
| Use | Web, app | Brochures, business cards | Brand-critical color (logo) |
What this means in practice¶
- A bright RGB color (e.g.,
#00B4FF) won't print as that color in CMYK. The press converts it to the nearest CMYK; result is duller, slightly shifted. - Test colors on press proofs before final run. A digital preview lies.
- Brand colors in print should be specified as Pantone (PMS) numbers, not just CMYK percentages. PMS guarantees consistency across print runs.
- Black: pure CMYK black is C:0 M:0 Y:0 K:100. Rich black (C:60 M:40 Y:40 K:100) prints darker and is used for large black areas. Don't use rich black for small text — registration mistakes show as colored fringes.
Designing in CMYK¶
Most workflows: design in InDesign / Illustrator / Affinity with CMYK color profile from the start. Don't design in RGB and convert at the end — colors will shift and the design must be re-checked.
For brand-critical pieces (business card, packaging): build the color palette in CMYK + Pantone references at the start of the project.
Resolution: DPI vs PPI¶
- PPI (pixels per inch) — for digital images, screens.
- DPI (dots per inch) — for printed output.
Practical rule: 300 DPI at final print size for photos. 600 DPI for line art / text-heavy.
If a photo is 1000×1000 pixels and the print size is 4×4 inches: 250 DPI — borderline acceptable. If print size is 8×8 inches: 125 DPI — visibly pixelated.
| Print size (inches) | Image size needed at 300 DPI |
|---|---|
| 2 × 3.5 (business card) | 600 × 1050 px |
| 4 × 6 (postcard) | 1200 × 1800 px |
| 8.5 × 11 (letter / A4-ish) | 2550 × 3300 px |
| 11 × 17 (tabloid / A3) | 3300 × 5100 px |
| 24 × 36 (poster) | 7200 × 10800 px |
For posters viewed from a distance: 150 DPI can be acceptable. For business cards held in the hand: 300+ DPI mandatory.
Bleed, trim, safe area¶
Print pieces have three concentric zones:
┌────────────────────────────────────┐
│ Bleed (3-5mm beyond trim) │ ← color extends here
│ │
│ ┌──────────────────────────┐ │
│ │ Trim (the final size) │ │ ← cutter cuts here (with ±1mm margin)
│ │ │ │
│ │ ┌────────────────────┐ │ │
│ │ │ Safe area │ │ │ ← keep text + critical content here
│ │ │ (3-5mm inside) │ │ │
│ │ │ │ │ │
│ │ └────────────────────┘ │ │
│ └──────────────────────────┘ │
│ │
└────────────────────────────────────┘
| Zone | Purpose | Typical size |
|---|---|---|
| Bleed | Color extends past trim so cut doesn't show white edge | 3mm (Korean standard), 0.125" / 3.175mm (US) |
| Trim | Final size of the piece | Per design |
| Safe area | Critical content (text, logo) that won't get cut | 3-5mm inside trim |
Why this matters¶
Cutters have ±1mm tolerance. Without bleed, a slight cut shift = white sliver on the edge. Without safe area, text gets clipped.
Set up your file with bleed from the start in InDesign / Illustrator. Don't try to add bleed after.
Common sizes (Korean / international)¶
| Name | Dimensions (mm) | Use |
|---|---|---|
| Korean 명함 (business card) | 90 × 50 | Korean business card |
| International business card | 85 × 55 | Most Western markets |
| A4 | 210 × 297 | Letters, brochures |
| A5 | 148 × 210 | Half-letter, leaflets |
| A6 | 105 × 148 | Postcards |
| A3 | 297 × 420 | Posters (small) |
| A2 | 420 × 594 | Posters (medium) |
| A1 | 594 × 841 | Posters (large) |
| A0 | 841 × 1189 | Posters (huge) |
| DL | 99 × 210 | Tri-fold envelopes / flyers |
Korean default for most marketing pieces: A4 / A5 / 명함. International default: Letter (216 × 279mm) is rare in Korea.
Paper: weight, finish, type¶
Weight (gsm — grams per square meter)¶
| gsm | Feel | Use |
|---|---|---|
| 70-90 | Thin, see-through | Inside book pages, drafts |
| 100-120 | Standard letterhead | Stationery |
| 150-180 | Light card | Postcards, leaflets |
| 200-250 | Sturdy card | Quality flyers |
| 300+ | Heavy card | Business cards, premium print |
| 350-400 | Very heavy | Premium business cards, packaging |
Korean business cards typically: 250-300gsm. Premium: 350gsm with finish.
Finish¶
| Finish | Look | Feel | Use |
|---|---|---|---|
| Matte / 무광 | No reflection | Soft, premium | Most B2B materials |
| Glossy / 유광 | High reflection | Slick | Brochures with photos |
| Satin / Silk | Mid | Smooth | Magazines |
| Uncoated | None | Natural texture | Letterhead, environmental brands |
| Soft-touch | Velvety | Premium | High-end business cards |
| Linen | Textured | Tactile | Wedding stationery, formal |
Different finishes change perceived brand: - Matte = professional, calm, premium-modern. - Glossy = energetic, inexpensive (mass-market), or premium-photo-led. - Uncoated = environmental, artisanal, raw. - Soft-touch = luxury, modern.
Special finishes (premium)¶
- Spot UV — glossy varnish on specific areas (logo). Adds tactile contrast on matte stock.
- Foil stamp / 박 — metallic gold / silver / copper / holographic. Premium signal.
- Emboss / 양각 — raised areas (logo). Tactile, classic.
- Deboss / 음각 — recessed areas. Subtle, modern.
- Letterpress — antique-feel impression. Wedding / luxury stationery.
- Die-cut / 도무송 — custom shapes (rounded corners, unique silhouettes).
Each of these adds significant cost (often 2-5× standard print).
File preparation checklist¶
Before sending to print:
- Color mode: CMYK (not RGB)
- Resolution: 300 DPI at final size for photos / raster
- Vector elements stay vector (logos, type)
- Bleed: 3mm minimum on all sides
- Safe area: 3-5mm inside trim for text
- Fonts: outlined OR licensed for embedding
- Ink coverage: total ≤ 300% (some printers say 280%) — sum of CMYK percentages
- Black: pure 100% K for small text; rich black (60/40/40/100) only for large fills
- Spot colors: defined as Pantone, not converted to CMYK silently
- Final size is correct (Korean 명함 vs international card differ)
- Crop marks + bleed marks included in PDF export
- PDF version: PDF/X-1a or PDF/X-4 (printer's spec)
- File embedded all images (no linked external paths)
- Spell-check Korean + English (printers don't proofread)
- Final proof signed off by client (don't print without)
File formats¶
| Format | Use |
|---|---|
| PDF/X-1a | Most reliable for print; flat CMYK |
| PDF/X-4 | Newer; supports transparency |
| AI | Adobe Illustrator native (vector source) |
| INDD | InDesign (multi-page documents) |
| TIFF | High-quality raster |
| EPS | Older vector format; still accepted |
Default for delivery: PDF/X-1a with bleed + crop marks. Provide source files (AI / INDD) if requested.
Color management — ICC profiles¶
Different printers have different presses with different color characteristics. Match output to the printer's ICC profile:
- Korean coated paper press: typically
Japan Color 2001 Coatedor printer-specific profile. - US sheet-fed:
U.S. Web Coated (SWOP) v2. - EU print:
ISO Coated v2 (ECI).
Ask the printer for their preferred profile. Embed it in the PDF export. Without ICC matching, colors shift.
Cost drivers¶
Things that increase cost: - Quantity (lower per-unit at high volume; minimum cost at low volume) - Color count (1-color < 4-color CMYK < CMYK + spot) - Paper weight + finish (heavier / specialty stock = more) - Special finishes (foil, spot UV, emboss, die-cut) - Double-sided (~1.4× single-sided, not 2×) - Variable data (each piece personalized — premium digital print) - Rush turnaround (3-day vs 7-day vs 14-day)
For pricing: get quotes from 2-3 Korean printers (충무로, 을지로 area, online platforms like Snaps, Vistaprint Korea).
Korean print market¶
- Major print districts: 충무로 (specialty / quality), 을지로 (variety / volume), 인천 (large-scale runs).
- Online services: Snaps, Bizhows, 컴인쇄, Vistaprint Korea — convenient, mid-quality.
- Premium: Designhouse, traditional print shops with letterpress / foil expertise.
- Standard turnaround: 3-7 days for standard orders; rush 1-2 days at premium.
- Minimum orders: business cards typically 100-200 minimum; flyers / brochures 500-1000 minimum at most printers.
For mass / cheap: online platforms. For brand-critical (business cards, premium brochures): traditional printer with sample proof.
See korean-print-conventions.md for Korean-specific format and content rules.
Don't¶
- Don't design in RGB and convert at the end — colors shift unpredictably. Start in CMYK.
- Don't ignore bleed — the 1mm cut tolerance will leave white slivers.
- Don't use 72 DPI photos for print — they pixelate even at small sizes.
- Don't trust digital preview for color accuracy — get a press proof for brand-critical work.
- Don't use rich black for small text — registration shifts cause colored fringes.
- Don't ship a file with linked images instead of embedded — printer might miss them.
- Don't change the design after the press starts. Re-runs are full price.
Cross-reference¶
knowledge/print/stationery.md— business cards, letterhead, envelopesknowledge/print/brochures-and-flyers.md— multi-page + folded piecesknowledge/print/signage-and-posters.md— large formatknowledge/print/packaging.md— boxes, labels, dielinesknowledge/print/korean-print-conventions.md— KR-specificknowledge/typography/type-scale-fundamentals.md— typography fundamentalsknowledge/colors/color-theory.md— color theoryknowledge/patterns/brand-identity.md— brand foundation