Selecting paperboard for graphical applications
- Book covers
- Sales folders
- Map covers
A substrate for imagination
Paperboard is a well established material for printed covers of all kinds; covers for books, brochures, advertising materials, reports etc. These applications have various purposes and therefore place somewhat different demands on the paperboard properties. For book covers durability is essential - a feature which is less important for brochures and short-lived advertising materials.
It is necessary that the creative and functional design of the cover reflects the contents. Covers often demand advanced graphical designs and printing techniques to create, in a visual way, an impression and expectation of the contents of the book, brochure etc. At the same time the cover must provide physical protection. A wide range of options are available. Starting with an empty white sheet, they are practically unlimited. The designer just has to add insight, feelings, fantasy, and know-how - designing covers is a craft of its own.
Choice of paperboard
The shelf appeal of a book cover is essential at the point of sale. But, the shelf appeal is also required after the purchase, since we expect the book to be attractive, expressive and easy to identify in our bookcase at home. For brochures and other sales promoting material, the role of the covers is somewhat different. The conveyed message is aimed at selling to us something which the brochure itself cannot provide - it may be an idea or a product concept. The cover promotes this idea by creating a distinct image of an, often unconscious, need; we are to be enticed to open the brochure and investigate its message.
The design of a brochure cover is required to be distinct, challenging and topical, whilst the design of a book cover may be more timeless. In both cases the visual impact is crucial. Very high print quality, with good contrast between the surface and the print, is required to achieve excellent graphical presentation of sharp half-tone illustrations or bold, strong colours in large solid areas. Important promotional characteristics of paperboard for all types of covers are whiteness, smoothness and surface finish, often required on both sides. Those properties are provided by the use of bleached virgin fibres and light fast coatings. The options of embossing, lamination and hot foil stamping, often used for prestigious covers, require surface strength.
A book cover is required to endure many years of use and storage in a bookcase without deteriorating in shape or appearance. This requires printed creases on the spine, which do not crack and which are durable to repeated opening and closing. The paperboard quality must prevent the graphical presentation from ageing and the corners from becoming dog-eared. Sales support material and brochures may not be needed to last for so many years - rather the contrary. But it is vital that the covers maintain their attractive appearance for as long as needed, without any deterioration in functional or graphical design.
Important protective characteristics of paperboard for covers are strength and toughness, folding rigidity and tearing resistance. A smooth surface provides for ease of handling. It also provides for good rub and abrasion resistance, thereby preserving the graphical presentation. Bleached virgin fibres, together with selected coating ingredients, ensure good light stability. The use of virgin fibres also provides for durable creases, edges and corners.
Printing and conversion
To obtain efficiency in printing and conversion a flat, stable and dust free paperboard is required. Good absorption and drying properties, as well as good cutting, creasing, embossing and gluing properties are important. Thus a high print quality is ensured, whilst process stoppages and material waste are minimised. For prestigious covers, produced in a multi-step process, paperboard with extremely good dimensional stability and exact sheet squareness is needed, to achieve perfect registration.
For efficient book binding, additional important factors are folding and gluing of the spine, delamination strength and good clean-cutting properties.