Three methods of determining the number of threads per centimetre are included, any of which may be used, the choice depending on the character of the fabric. The principles are as follows: Method A: A section of fabric of dimension specified is dissected and the number of threads counted. The treads that are to be counted are preferably short, 1 or 2 cm being suitable. Method B: the number of threads visible within the aperture of a defined counting glass is determined. Method C: the number of threads per centimetre of the fabric is determined with the aid of a traversing thread counter.