In recent years, as Tibetan culture has generated great interest among foreigners and Chinese in other regions, Thangka has been in great demand.

The word "Thangka" is derived from the transliteration of a Tibetan phrase that means "the unfolded picture."

Thangkas first appeared around the seventh century. Nowadays, thousands of Thangkas can be seen in the Palace Museum in Beijing.

Some were presented as gifts to emperors of the Qing Dynasty (1644-1911). They had been carried to the capital by former kings of minor nationalities from western China -- including Tibet, Gansu, Qinghai and Inner Mongolia.

Other Thangkas were painted by royal artists of that era.

Thangkas combine the Chinese scroll painting with Nepalese painting techniques and Kashmiri painting styles. They often depict brightly coloured iconographic figures such as peaceful buddhas, fierce deities residing in their fiery realms or glorious heavens and "sky beings" called dakinis.

There are several categories of Thangkas -- including the painted Thangka, which is the most common; the woven Thangka; the embroidered Thangka; and the pasted Thangka.

Cotton canvas and linen cloth are the common fabrics on which pictures are painted, with mineral and organic pigments. In particular, gold and gemstones are used as pigments for important Thangkas.

The complex designs and colours are symbolic, and commonly commissioned to decorate monasteries, temple walls and families' homes.

Thangkas deal with various subjects -- including Tibetan astrology, pharmacology, theology, images of great adepts, deities and Buddhas.

A typical Thangka has a picture, either printed or embroidered, mounted on a piece of colourful silk.

Thangkas, which are rectangular, are usually placed upright. A wooden stick is attached, from side to side, on the bottom, to make it easier to hang and roll up.

Thangkas, which are rich in religious, art and archaeological value, have set records at art auctions in recent years.

One Thangka in particular, a huge embroidered image entitled "Red Monster," considered a rarely seen Tibetan Buddhist treasure, sold for HK$30.87 million (US$3.94 million) during an auction in Hong Kong in 2002.

It set a record in Asia for a fabric-related auction.

It took artists several weeks, at least, to create a refined Thangka. In some cases, it could take years.

Analysts advise people to watch a painter at work -- so they will appreciate the painstaking process -- before buying a Thangka.

They also suggest potential customers study the imagery and meaning behind the Thangka.

For example, a bright, unpainted background is most common. Red and gold backgrounds generally depict peaceful deities, while a black background reveals angry deities emerging from impenetrable darkness.

Different gestures express different meanings.

When you find a Thangka you like, examine the details -- eyes, facial expressions and fingers of the major figures. Background figures should also stand up to scrutiny.

Real gold should not come off the Thangka if you press your moist finger against it.

A reasonable small (15x30 centimetre) Thangka should cost at least 300 yuan (US$35.10).

A large (90x120 centimetre) Thangka, on which microscopic brushstrokes and genuine gold paint were used, could cost hundreds or even thousands of US dollars.

If you purchase a Thangka at a surprisingly low price, you most likely bought a so-called "Junk Thangka."

Such Thangkas are intended for tourists. They are generally produced within days, and they lack the intricacy, refinement and artists' devotion of a nice Thangka.

Thangkas should not be exposed to excessive sunlight. They should be stored in temperatures between 15-18 C. Excessive humidity, above 60 per cent, can damage the Thangka's mineral and organic colours.