Paper and Board Materials: Types, Properties and Selection
This domain tests whether you can name paper and board types, state the properties that decide their use, and justify a selection for a specific binding job. Expect a product - a textbook, a photo album, a sweet box - with questions on grade, GSM range or a property such as grain direction.
Core properties
- GSM (g/m²) is grammage or substance; caliper is thickness in mm or microns; bulk = caliper ÷ GSM, so two 80 GSM papers can differ in thickness.
- Grain direction follows the machine direction of the fibres. Fold and bind with grain parallel to the spine, or the pages cockle and the fore-edge ripples.
- Opacity controls show-through, brightness affects print contrast, sizing controls ink and water absorption, pH decides archival life, and tear strength decides fold endurance.
Selection rules
- Book text: 60–80 GSM cream wove or maplitho for novels; 90–120 GSM for heavily illustrated textbooks; art paper only where halftones matter.
- Endpapers: 100–120 GSM, because they carry the hinge strain.
- Paperback cover: 250–300 GSM art card, usually laminated.
- Hard case: 1.5–2 mm millboard covered with cloth, rexine or buckram.
- Cartons: 3-ply or 5-ply corrugated; E-flute for small, fine boxes.
Worked example
A 96-page A5 notebook, hardbound. Leaves = 96 ÷ 2 = 48. At caliper 0.10 mm the block is 48 × 0.10 = 4.8 mm. Choose 80 GSM maplitho text (opaque enough for printing both sides), 120 GSM endpaper and 1.5 mm millboard rather than 2.5 mm, because thick boards on a thin block look clumsy and make the book open badly.
Traps
- Equating high GSM with high thickness; bulk changes with finish and calendering.
- Choosing glossy art paper for a workbook meant for pencil writing.
- Ignoring grain direction until the book ripples after casing-in.