Papers and Boards

From Wood Pulp to Printed Page

Paper and board are among the oldest industrial materials, yet they remain central to modern design—from product packaging to architectural models. Both begin as wood pulp, produced either mechanically (grinding logs into fibres) or chemically (using reagents to dissolve lignin and release clean cellulose). Chemical pulp produces stronger, longer-lasting sheets; mechanical pulp is cheaper but yellows over time because lignin remains in the fibres.

Paper is measured in two ways. Grammage (gsm) describes mass per unit area. Copy paper is typically 80 gsm; a premium business card may be 350 gsm. Microns describe physical thickness: standard copy paper sits around 100 microns. The two figures usually move together, but coated papers can be heavier per micron than uncoated ones because the coating adds density without adding much bulk.

ISO Paper Sizes

The international standard for paper sizing is the ISO 216 series. The A-series is built on a single mathematical relationship: each size is exactly half the area of the one above it, and the aspect ratio remains constant at 1:√2 (approximately 1:1.414). This means an A3 sheet folded in half gives two A4 sheets, an A4 folded in half gives two A5 sheets, and so on. A0 has an area of exactly 1 m². Designers use this relationship routinely when scaling artwork: an image laid out on A3 will reproduce correctly at A4 without distortion.

The B-series covers intermediate sizes (useful for posters and passports), and the C-series is used for envelopes (a C4 envelope holds an A4 sheet flat). In practice, the A-series is what designers, printers and students encounter daily.

Types of Paper

Layout paper is thin and slightly translucent—ideal for developing ideas quickly in pencil. Designers layer sheets over earlier sketches to refine forms without starting from scratch. Tracing paper is more transparent still, used to copy existing drawings accurately. Cartridge paper is the general-purpose drawing paper used in most D&T studios: heavier than layout paper (typically 100–140 gsm), with a slightly textured surface that holds pencil and ink well. Bleed-proof paper has an extra smooth coating that stops alcohol-based markers bleeding through to the sheet beneath.

Recycled paper is made from post-consumer waste fibres that have been de-inked and re-pulped. Each recycling cycle shortens the fibres slightly, which reduces strength over successive cycles, but modern paper can contain 100% recycled content for many applications. Recycled paper typically has a slightly grey or cream tint rather than the bright white of virgin-fibre sheets, because optical brightening agents (OBAs) are harder to apply uniformly to recycled pulp.

Types of Board

Boards are heavier-duty sheets, generally above 200 gsm, produced by laminating multiple paper layers together or using a thicker single-ply process. The main boards used in GCSE D&T are:

• Corrugated board—a sandwich of flat liners bonded to a fluted inner layer. The fluting creates a rigid structure that is surprisingly light. Used in protective transit packaging and models. Typically 3 mm to 5 mm thick but weighs far less than solid card of the same thickness.
• Folding boxboard (FBB)—a multi-layer board with a white coated surface ideal for high-quality printing. Used in cereal boxes, medicine packets and cosmetic packaging. The inner layers may contain mechanical pulp to reduce cost, with a chemical-pulp surface layer for printability.
• Mounting board—a thick, rigid board (1.5–3 mm) used to mount and present artwork or photographs. Available in many colours. Commonly used by designers to present rendered illustrations or to produce scale architectural models.

Laminating and Finishing

Laminating applies a thin plastic film (typically polypropylene) to a printed sheet. Gloss laminate intensifies colour and reflects light; matt laminate reduces glare and gives a softer feel. Both significantly improve the product’s resistance to moisture, tearing and everyday handling. Laminating is common on book covers, loyalty cards and food packaging where the printed surface must survive repeated handling.

Other finishes include spot UV varnish (a glossy coating applied to specific areas only to create contrast), embossing (pressing a design into the board to create a raised surface) and foil blocking (applying a metallic foil under heat and pressure). Each adds cost and requires specialist equipment, but can significantly increase the perceived quality of a product.