The Complete Guide to Paper: From Raw Materials to Applications

Have you ever wondered how the paper you use every day is made? What’s the difference between various types of paper? This article will take you through the ins and outs of paper.

1. What Paper Is Made Of: Fibers and Additives Working Together

Main raw materials (plant fibers):

  • Wood, reeds, bamboo
  • Sugarcane bagasse, rice straw, wheat straw
  • Tree bark, cotton, hemp, etc.

Additives:

  • Fillers (e.g., clay, talc): fill gaps between fibers
  • Sizing agents: improve strength and smoothness
  • Dyes: for tinting or coloring – even white paper needs treatment

2. Specialty Papers: Types and Structure of Gold/Silver Cardboard

TypeComposition
Aluminum foil basedAluminum + backing paper + varnish + print
PET basedFilm + backing paper + varnish + print
HolographicFilm + aluminum + embossing + backing paper + varnish + print

Note: Gold card is made by dyeing silver card (coated with red or yellow pigment), so its adhesion is generally weaker than that of silver card.

3. Paper Quality Evaluation Criteria

Visual quality

  • Uniformity: even distribution of fibers and thickness
  • Cleanliness: surface free from dirt and spots
  • Flatness: smooth and even

Physical properties

  • Squareness, caliper, density
  • Opacity, dirt count
  • Tensile strength, folding endurance, tear resistance

4. Paper Sizes Explained

Packaging formats

  • Sheet-fed: pre-cut by the mill, good flatness
  • Roll: wound on a core
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Common sizes

TypeDimensions (mm)Inches
Large format889 × 119435″ × 47″
Standard format787 × 109231″ × 43″
Special formatAny size other than abovee.g., 25″ × 38″

5. Thickness vs. Grammage Reference Tables

Note: 1 “si” (Chinese unit) = 0.01 mm. Values vary by manufacturer and process; for reference only.

Coated paper (art paper)

GrammageThickness (si)
80 gsm5–6
105 gsm7–8
128 gsm10–11
157 gsm12–13
200 gsm16–17
230 gsm19
250 gsm22

Coated board

GrammageThickness (si)
230 gsm22–26
250 gsm26–27
300 gsm30–31
350 gsm35–37

Matte coated paper is about 2 si thicker than gloss coated paper of the same weight.

White card (solid bleached board)

GrammageThickness (si)
230 gsm29–30
250 gsm35
300 gsm40
350 gsm47–48
400 gsm52

White-backed white board / gray board

GrammageThickness (si)
250 gsm white back28
450 gsm white back57
250 gsm gray back28
300 gsm gray back36
350 gsm gray back42
400 gsm gray back49
450 gsm gray back57

Woodfree offset paper

GrammageThickness (si)
70 gsm8
80 gsm9
100 gsm11
120 gsm13
140 gsm16

Kraft paper

GrammageThickness (si)Notes
80 gsm11
120 gsm14
150 gsm16–1818 typical, 16 special
200 gsm22
300 gsm44

6. Practical Conversions and Selection Tips

How to choose:

  1. Brochures: 157–250 gsm coated paper
  2. Business cards: 300–350 gsm coated board or white card – specialty paper for a premium feel
  3. Book interiors: 70–120 gsm woodfree offset paper
  4. Packaging boxes: 250–400 gsm gray board or white card
  5. Envelopes/file folders: 80–150 gsm kraft paper

Thickness reference (everyday items):

  • Standard A4 printer paper: about 8–9 si
  • Typical business card: 30–35 si
  • Hardcover book cover: 40–50 si
  • High-end gift box: over 50 si

With this guide, you now have a solid understanding of paper raw materials, types, specifications, and quality standards. Whether for daily use or professional selection, this knowledge will help you make better decisions.