What is a Tartan?

A simple definition of tartan

Defining a tartan is not as simple as it might first appear because for whatever criteria are dictated, there are bound to be some 'tartans' that defy the convention. However, here is a simple definition - allbeit couched with qualifications.

Tartan is a unique art form and conventionally a textile design comprising woven bands or stripes of various colours and widths, the design sequence being the same in both directions of the fabric - with some exceptions - and normally producing a square pattern which is generally - but not necessarily - symmetrical about defined pivot points or stripes.
This arrangement creates a recognisable pattern or 'sett' which is repeated across the width (weft) and length (warp) of the material. Where bands of differing colours cross, intermediate hues are formed and the pattern can be modified by the addition of finer lines of the same or contrasting colours.
This definition is not to the exclusion of designs which - displaying the identifying characteristics of tartans - are destined for use in other than woven form.

For a much more detailed and erudite discussion see the article by the late Jamie Scarlett MBE.

Don't be intimidated by that M=1/2[N2-N] formula in the banner! One of the great aesthetic attractions of woven tartan is that not only does it comprise the pure colours that you or the weaver chose, but it also comprises various different shades where one pure colour crosses another. It's that characteristic that gives tartan its fascinating range of shades that can alter very subtly depending upon how the light falls on the fabric.

As Jamie Scarlett puts it in his article: "The twill weave produces a diagonal ribbing in the cloth and the two colours appear as alternate lines and not as 'pepper and salt' as they would in a plain-woven cloth. The number of mixed colours increases rapidly out of proportion to number of 'starter' colours, in accordance with the formula M = ½[N2 - N] where M is the number of mixtures and N the number of 'starter' colours. Two 'starter' colours give one mixture and seven, the normal maximum, give twenty-one."