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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 Coated or 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