Brussels and Wilton carpets are described as being of five, four, or three frames, according to the number of sets of creel bobbins carrying worsted warp threads. Each frame will generally be composed of threads all of one colour; but an enhanced colour effect is often obtained by one or more of the frames being “planted.” This means that worsted threads of two or more colours are arranged side by side in the same frame in groups, in accordance with the design. If, for instance, the design contains a rose, for the petals of which a frame of pink yarn is to be used, then the colourist or weaver, by a judicious selection and arrangement of bobbins, can add to the colour effect by shading the petals from light to dark; or, again, a flower may be coloured blue in one part of the design and gold in another. Skilfully used, this device makes a three-frame look like a four, or a five-frame like a six, but it must be used with discretion and with due regard to the design, or disfiguring and tell-tale stripes will ensue.
[Illustration: FIG. 3 SECTION OF FIVE-FRAME BRUSSELS CARPET A A, Chain; B, Pile warp; C, Stuffer warp]
Best Brussels has been taken as an example in describing the process of manufacture, but a good many other qualities are, or at least have been, made. Best is 256 pitch, beaten up 9 to the inch, but extra qualities are made up to 11 per inch, which gives an excellently close and even surface. Finer than this in pitch or beat-up it has not been found practicable to go. Lower qualities are made in 236 and 214 pitch, and even down to 180, with beat-ups running down to 6½ or 6 per inch, and a framage of three or two. In the coarsest qualities, however, there is always the tendency to “grin,” that is, for the weft and body of the carpet to be exposed between the loops of the pile, unless the coarseness is compensated by the employment of a thicker pile yarn or a higher wire. This is, in fact, the case with a class of Brussels that has been manufactured extensively by some makers in recent years, where the yarn is spun from low wool or cow-hair, and is a good deal heavier than the ordinary Brussels worsted counts. This fabric is almost entirely confined to plains and stripes, though occasionally two frames are used, and a simple pattern effect produced. It is a good wearing carpet, and suitable for offices and modest purses.