It is common knowledge that a conventionally woven textile consists of two assemblies of parallel threads (warp and weft), one interlaced with the other at ninety degrees. Where each of the two assemblies is arranged in a particular colour sequence, a check design, known as a ‘tartan’, may be created. Although similar check-type cloths have been produced worldwide, it is the tartans of Scotland which have received most attention and it is here that a complex set of rules evolved and tartans of different types became associated traditionally with different regions, family groups or 'clans'. There is an impressive array of publications focused on the identification of tartans and their clan associations. This paper explains the nature of tartans, analyses typical surface structures, ratios and proportions, and suggests possible avenues of use for modern designers. The principal sources of data were a collection of tartans held at ULITA - An Archive of International Textiles (University of Leeds, UK) and Stewart's 1974 publication The Setts of Scottish Tartans. Based on the observation that divisions into halfs and thirds were dominant, a series of templates is presented with the intention of developing an awareness among designers that ratios and proportions used in familiar or traditional frameworks can be employed in a modern context.