The practice of printing manuscript and prayer flag is very much depended upon the beliefs of Tibetan religious life. Actually this process was introduced from China to Tibet for some kind of religious need. Therefore it cannot be compared with modern day fine print making.
So for appreciating this tradition fully, we need to understand the social, cultural and religious beliefs of Tibetan community. Then it will be much clear to us, how this technique got a fertile ground for its development in this particular community.
    Tibet had one kind of a Shamanistic belief which was originated at her own ground. The beginning of this belief is quiet uncertain as presence of such animistic religion is common in the beginning of any human society. The name of this pre-Buddhist Tibetan folk religion is BON-PO.Practice of this religion was magical rites, sacrifice and worship of wrathful deities. From this inheritance an ever lasting attraction toward magical performances and Shamanistic approach was well grooved in the depth of Tibetan mind.
     Buddhism was first introduced in Tibet in time of king Songsten Gampo in 6th century. Mahayana or ‘Greater vehicle’ or ‘northern Buddhism’ was introduced there. In Emperor Trisong Detsen’s reign Indian Buddhist monk and scholar Santarakhshita, was invited to Tibet. He established Tibet’s first monastery at Samye. At that time tantric guru PadmaSambhava, the most respected religious hero of Tibet came from Swatt valley of Pakistan. He is often called Vajra gura Rimpoche in Tibetan. When Guru Padma Sambhava came, he saw the entire land is spellbound by Bonpo priests. He converted the followers of Bonpo religion to Buddhism, assimilated some of their occult practices and accepted some Bonpo deities in Mahayana iconography as wrathful delties or Dharmapalas (Dharma Protecting deities). Actually it was guru PadmaSambhava, for whose effort Buddhism took the most important place in Tibetan life for centuries .
    The Schools of Tibetan Buddhism derived from Indian Mahayana tradition. The four main Schools are (1) NYINGMAPA ( the old school) founded 8th centuries by Guru Rimpoche. (2) SAKYAPA whcih schools Indian lineage derived for mahasiddha Birupa, an enlighened tantrika and transmitted to Tibet by Drokmi Lotsawa. (3)KAGYUPA school was founded arround 10th -11th century. The lineage of them is derived from Indian mahasiddha Tilopa to Naropa to Marpa and to Milarepa.
The KADAMPA school was founded be Atisha Dipankara (10-47-54), famous Buddhist scholer from Bengal, Later it was absorbed by the fourth major school - GYELUKPA (The yellow hat) School. This school was founded by Tsonkhapa. He had his lineage from Dipankara's disciple Dom-Stonpa. Dalai Lama, the religious leader of Tibetan Buddhists, comes from this gyelukpa sect. There are few other sects also besides these major schools.
   However all these sects belong to Mahayana tradition and their teaching and practice put great emphasis on studying Mahayana sutras, and practice of meditation, tantra and yoga; although the practice varies from school to School.
   So for this study of Buddhist philosophy a huge amount of Buddhist texts to Tibetan language. They did this huge job between 7th to 13th Century with the pely of Indian scholars. All the manuscript we find this period is hand-written.
   Tibetan emperor Songtsen Gampo commissioned his minister Thonmi - Sambhot for devloping a Tibetan script. Thomni Sambhot adapted Sanskrit alphabet and made Tibetan phonetic script based on Brahmi  . The Tibetan scripture is mainly two types ‘Uchen’ and ‘Umed’. ‘Uchen’ is formal script and ‘Umed’ is used for quick writing. generally ‘uchen’ is used in every types of text writing.
After 14th century when the craft of printing was introduced from china to Tibet, the Tibetan took the advantage of this unique technology for copying this huge amount of texts. Buddhism always enjoyed great support and patronage from the ruler of the of the state and common people in Tibet. Numerous monasteries and universities were built in the entire country during the flourish of the religion. This gompas or monasteries were the main educational institution of this country. For the study of the students of this institutions, the mass production of texts was needed. So the practice of printing got a very enthusiastic atmosphere.
   But the expansion of use of printing on other areas beside copying manuscript was patronized by tantric practice. One of such area is printed banner or prayer flags. The type of Tantric ways and ritual practiced among Tibetan community is Mantrayana or the vehicle of Mantra. In this way mantra is considered the chief means of salvation. A mantra is thought as a condensed and most concentrated expression of an energy or concept within a few sounds. Art historian Philip Rawson wrote about this:-
“A mantra is felt to be a sort of nucleus on gathering point for, energy or concentrated from of cosmic power. To utter one correctly (Which needs patient study and effort) evokes from the interfused structure of man and cosmos for the specific force to which is related”.
So according to such belief reciting the mantra repeatedly is a method of attaining spiritual merit of the practitioner -
“The mantras which concern us here, however are those with a ritual purpose. They may be recited voiced on voicelessly, thousand of times over in what is called ‘JAPA’, so as to produce a cumulative stream of energy. On cloth mantras may be woven or printed many times over as a visual equivalent of Japa”.
     In any monastery, village or locality of Tibetan community, we see men and women are doing japa by counting beads or with japayantra- a cylindrical device at one side of which a bead is hanging and it is rotating along its axis on a small stick attached at its bottom. This japa is the commonest and widest used way for common people as spiritual practice.
So this process of japa is transferred as an visual expression of mantra to banner and prayer flags by means of printing. These prayer flags, It is believed, when lifted, it purifies the air with the mantra and by air the mantra flow across the space as a prayer of the person who raised it.
    Whether this belief has originated from Shamanistic bon practice or Mahayana tradition can not be surely ascertained. Such faith is also very common in Indian mind because Tibetan mind share so much common elements at the base of their culture with the Indians. This wish to sanctify the environment, house on the surrounding and make it worth a place for a deity is not different from the wish to purify the air with mantra printed on prayer flags. Famous artist and theoritician K.G. Subramanyan wrote in his essay "Religion and art in India"-
"One can trace the Indian concept of metamorphosis rebirth and trans-substantiation to such a vision. The persistent in Indian notion of life also probably derives from this. So a devout Indian wishes to transform his house into a temple, his life into a holy pageant, he wants to see every thing in his environment transformed, with its ‘ animus’ glowing. His greatest desire is to transform and rarefy himself, and, at the ultimate, to come off his ‘costume’and to be ‘free’, or as he would say, attain final release or ‘mukti’.
  The recognition of this idea of transformation and flux as an essential part of Indian life will make it easy for one to under stand Indian art forms and Indian art activities in proper perspective".
    This desire for sanctification of environment, transform everything into a transcendental condition and inviting the auspicious is a common driving force of art activity in this region. Here in prayer flags the mantra sanctify the environment.
    The most auspicious mantra printed is ‘om mani peme hum’. Which is considered as mantra of ‘CHENREJIG’(Avolokiteshwara) In its fabric compounds ‘om’ is root syllable of origination, ‘MANI’ means jewel, synonym to ‘vajra’, the word which means ‘thunderbolt’ or ‘wisdom’, ‘PEME’ means ‘padme’ or ‘in the lotus’ or ‘compassion’, ‘Hum’ means the nuclear mantra which represents, Buddha, highest enlightened being. So the mantra ‘OM MANI PEME HUM’ represents the concept of inseparability of wisdom and compassion in Vajrayana Buddhism(7). But this six syllable mantra is also believed by the devotees as a way of salvation where the six syllable repreasents the six worlds of Hell, Human beings, animals, demigods, gods and hungry ghosts and who recites the mantra get salvation from these six worlds.
      The twelve syllable mantra ‘OM AH HUNG VAJRA GURU PEME SIDDHI HUM’ is considered as Vajraguru PadmaSambhava’s mantra and evolves his blessing. This is printed in Vajraguru Thurchok.
   At this discussion now we come to the point that the development and patronization of this art form is dependant upon some different type of need compared to modern day practice of art Apart from being a specialized discipline named fine Art which enjoy the specialized discipline the glamour of high culture, this practice of printing craft became deeply attached with social and cultural life of the community. It does not relish the exhibition value of an art object but always appraised by a different scale of value – the cult value. Famous German Art theoretician wrote in his essay, "The work of art in the age of mechanical reproduction"-
  "Originally the contextual integration of art in tradition found its expression in the cult. We know that the earliest art works originated in the service of a ritual-first the magical, then the religious kind. is significant that the existence of work of art with reference to its aura is never entirely repeated from its ritual function, In the other words the unique value of the authentic work of art has Its basis in ritual the location of its original use value".
He further made it distinct that any art could be valued by this different kind of valuation–
  ‘‘Works of art are received and valued on different planes. Two polar types stand out. With one the accent is on the cult value, with the other, on the exhibition value of work’’.
    While discussing about traditional form of printing one should keep these two different scale of valuation for better appreciation of this heritage.