In some cases, obi can provide a chance for a designer to show his skills, since the colors that can be used (or the number of plates for printing) is limited by a budget, and balance must be kept with the type of paper used with the cover of the book.
場合によっては予算の都合で使える色の数（というより印刷の版の数）が少ないこともあり、用紙や、表紙との兼ね合いから、デザイナーの腕の見せ所となる。