[citation needed] When creating a Buddha image, the artist is expected to be in a spiritual and mental state (samādhi) that will enable him to visualise this ideal reality.
[citation needed] The current range of postures in which the Buddha may be shown, and the gestures which may be depicted, evolved over the first millennium of the Buddhist era (roughly 500 BCE to 500 CE), mainly in India, the original homeland of Buddhism.
The tradition of images that reached South-East Asia had been changed in the later 5th century CE, apparently first at Sarnath in India.
[2] In the early part of this period, the Buddha was usually shown giving a general gesture of benediction, with the right hand held at shoulder-height with the palm facing forward and the fingers together and slightly bent.
By the end of the Gupta Empire (about 550 CE), the canon of representation had become more varied, with the seated meditative position (dhyāna mudrā – see below) becoming common, particularly in Sri Lanka.
This canon was not formalised until the 19th century, as part of the general project of "modernisation" that followed the Buddhist world's encounter with Western civilisation.
At the request of King Rama III, Paramanuchit described and represented 40 different postures of the Buddha in an illustrated treatise called Pathama Sambodhikatha.
Paramanuchit's illustrations were later rendered as bronze miniatures, which can be seen today at Wat Phra Kaew in Bangkok and serve as templates for the creation of modern Buddhist imagery.
Some of these are poetic or fanciful ("legs like an antelope's," "ankles like rounded shells"), while others are more specific: feet with level tread, projecting heels, long and slender fingers and toes, a tuft of hair between the eyebrows.
These gestures have meanings which are known throughout the Buddhist world, and when combined with the postures described above, give a complete representation, usually associated with a particular incident in the life of the Buddha.