Historically: it is believed that the first graphite pencil "yellowed" about 1890, and made it special was - they say, so it will be easier to find on the desktop. But the history of ordinary pencils are much older than you think.
At the beginning of the XIX-th century in America graphite supplied from China, in connection with the sellers of office supplies would like to emphasize that their products are imported from distant mysterious Asian country. In China, yellow - the color of reverence and respect, which is why American retailers have begun to paint him in the Chinese graphite pencils - thus they sought to emphasize the quality of the product. However, according to the historian Henry Petroski (Henry Petroski), the first company to think of that marketing course, was a Czech company «Koh-i-Noor Hardtmuth». Today, the majority slate pencils sold in the market, the yellow, but now it no longer means "elite" of the origin, rather, it is a tribute to tradition.