tartan is recorded by counting the threads of each colour that appear in the sett. the "thread count" not only describes the width of the stripes on a sett, but also the colours used. for example, the thread count "k4 r24 k24 y4" corresponds to 4 "black" threads, 24 "red" threads, 24 "black" threads, 4 "yellow" threads. the first and last threads of the thread count are the pivot points. though thread counts are indeed quite specific, they can be modified in certain circumstances, depending on the desired size of the tartan. for example, the sett of a tartan (about 6 inches) may be too large to fit upon the face of a necktie. in this case the thread count has to be reduced "in proportion" (about 3 inches).