Selecting Cover Materials for Handmade Bookbinding

The cover of a hand-bound book is both a structural component and a surface material. It must protect the text block, allow the book to open and close repeatedly without cracking or delaminating, and hold adhesive without warping. Cover material selection involves understanding how each candidate material behaves when cut, folded, pasted, and used over time.

Board: The Structural Foundation

Most case bindings begin with binder's board — a dense, compressed grey or brown board cut to the dimensions of the text block. The board provides the rigid structural form of the cover. Its weight (expressed in grams per square metre or as a caliper thickness in millimetres) determines how stiff and heavy the finished cover will be.

For a standard journal or notebook with a text block of around A5 size (148 × 210 mm), binder's board in the range of 1.5–2.5 mm is common. Thinner boards (1–1.5 mm) suit smaller books or bindings where flexibility is desirable; thicker boards (2.5–3.5 mm) are appropriate for larger formats or books intended for heavy use.

Binder's board must be conditioned before use: it should be stored flat in a space with consistent humidity, and both sides should receive adhesive simultaneously to prevent differential expansion that causes warping. This is particularly relevant in Polish winters, where interior heating can produce very low relative humidity.

Common Board Thicknesses by Application

A6 pocket journals — 1.0–1.5 mm
A5 notebooks, sketchbooks — 1.5–2.5 mm
A4 large-format books — 2.5–3.5 mm
Conservation rebinding — matched to original where possible

Bookcloth

Bookcloth is the standard covering material for case bindings in commercial and craft bookbinding alike. It consists of a woven cloth backing coated or starch-filled to prevent adhesive penetration during covering. The coating also produces a surface that can be lettered with foil or printed by hand.

Traditional bookcloth (sometimes called "open weave" cloth or "super") is starched rather than coated; it allows some adhesive penetration, which contributes to adhesion but must be worked quickly before the adhesive sets into the weave. Modern coated bookcloth (often sold under trade names in the bookbinding supply market) is more forgiving — it can be adjusted and repositioned slightly before the adhesive cures.

Bookcloth is cut with a generous turn-in allowance — typically 15–20 mm on all sides — which folds over the board edges and adheres to the inside faces. The turn-in must be mitered at corners to avoid bulk. Mitering involves cutting the cloth at a 45-degree angle near each corner, leaving just enough material to wrap and overlap cleanly at the board edge.

Leather

Leather remains the most durable and traditionally prestigious cover material for hand-bound books. However, it is also the most demanding to work with, and not all leathers are appropriate for bookbinding. The critical property is "paring" tolerance — the ability to be thinned at edges and corners to produce a turn-in without visible bulk.

Goatskin and sheepskin are the most commonly used bookbinding leathers. Both can be pared with a paring knife or a leather paring machine to reduce thickness at turn-in edges. Calfskin (vellum) is used for conservation rebinding and historically significant work. Pigskin, which is harder to pare but very durable, appears in some German and Central European binding traditions.

In Poland, bookbinding leather is available from a small number of specialist suppliers; most workshops import from German or British suppliers who provide vegetable-tanned leathers appropriate for bookbinding. The distinction matters: chrome-tanned leather (common in the general leather goods market) is not appropriate for bookbinding because it off-gasses acids over time that can damage paper.

Vegetable-tanned leather, when correctly stored away from light and excessive humidity, does not require dressing or conditioning for decades after binding. Chrome-tanned leather can begin to deteriorate within years under adverse conditions.

Paste Paper and Decorative Papers

Paste paper is a hand-decorated paper made by applying coloured paste (traditionally wheat starch paste combined with pigment) to a dampened sheet and then working it into patterns with combs, brushes, or fingers. It is used as a covering material for boards, as endpapers, and as a decorative accent in combination with bookcloth or leather spines.

Paste paper covering requires a relatively heavy paper stock — around 90–120 gsm — to prevent tearing when wet paste is applied. The paper is dampened, paste is applied and worked, and then the sheet is allowed to dry completely before cutting and pasting onto boards. Warping is the primary risk during drying; sheets should be dried under boards or weights to keep them flat.

Marbled paper serves a similar decorative function. Historical Polish bookbinding incorporated marbled endpapers influenced by the trade routes that brought Turkish and Italian marbled papers into Central Europe from the 17th century onwards.

Paper Covers and Soft Cover Bindings

Not all books require board covers. Pamphlet bindings, zines, and short-run publications often use heavy card or heavy paper covers (220–300 gsm) rather than board. These are cut slightly larger than the text block and scored at the spine to allow clean folding. The covering material and the text block are then stitched together in a single operation — either as a saddle stitch pamphlet or a stapled format.

For journals that need flexibility — a book that can be rolled or stuffed into a bag — a soft cover in heavy card with a long stitch binding is a practical choice. The cover material must tolerate repeated flexing without cracking along the scored spine fold.

Adhesives for Cover Attachment

Paste (wheat starch or rice starch) and PVA (polyvinyl acetate) adhesive are the two standard options for adhering cover materials to boards. Paste allows more working time and is reversible — it can be re-wetted and repositioned, which is useful for leather and bookcloth. PVA provides a stronger, faster-setting bond and is less reversible once cured.

A common working approach is to mix paste and PVA in roughly equal proportions, producing an adhesive with moderate open time and adequate final bond strength. The exact ratio is adjusted for the specific material being adhered: leather requires more paste; bookcloth can tolerate more PVA.