These intermediary bands or subsidiary borders are very important in Eastern rugs and carpets, and their quantities very carefully considered. A Persian designer, for instance, would never leave a blank unbroken strip of colour to surround his field; his object is not to isolate the quantities of his pattern, but to distinguish and unite them: so he makes use of the subsidiary borders as additional quantities. A usual arrangement which always looks well is to have the border proper inclosed in two bands of about the same width and quantity in pattern—or they might be a repeat of each other—and to inclose the field or centre within another narrow subsidiary border. But the variations to be observed in any chance selection of Persian rugs or carpets are constant, and the amount of subtle variety and invention in these subsidiary borders is endless.
Very excellent examples of the treatment and distribution of quantities may also be studied in the older Indian printed cottons, such as maybe seen at South Kensington.
Contrast
The consideration of quantities in form and design involves the question of contrast, which, indeed, can hardly be separated from it. There is the contrast of form and line, and the contrast of colour and plane. It is with the first kind we are dealing now.
Take the simplest linear border, such as the type common in Greek work. We should easily weary of the continual repetition of such a form alone and unassisted, but add a vertical with an alternative dark filling, and we get a certain richness and solidity which is a relief at once. Add another quantity, and we get the rich effect of the egg and tongue or egg and dart moulding.
A still simpler instance of the use of contrast, however, is the chequer, or the principle of equal alternation of dark and light masses; but this touches colour contrast rather than form.
