Veiling spells are twofold: Firstly, they can conceal things under the Arcanum’s purview from detection: A target can be made to lose all sense of time (Time), a fire’s heat and light can be hidden from view (Forces), or a building made all but impossible to notice (Matter). Secondly, they can conceal a target from concrete phenomena under the Arcanum’s purview: a mage can render herself invisible to ghosts (Death), or ward a powerful Locus from detection by spirits (Spirit), or walk unnoticed through a crowd (Life or Mind), or past a camera (Forces).
Short of archmastery, it’s impossible to Veil something against an abstract concept or force: a mage can’t Veil herself against death or hide from time, for example.
In Game:
In general, the larger or more complex the creature, place or thing to be affected, the more Arcana dots, Reach or Spell Factors the mage needs in the appropriate areas. These spells are also subtle in aspect as well as meant to be used for secrecy.
This twofold subtlety serves to make Veiling effects especially popular among spies, thieves and even assassins. Such subtlety also makes the Practice of Veiling a fantastic toolkit for performing otherwise dangerously blatant magic in the vicinity of Sleepers without (as much) fear of Paradox or Dissonance.
A cunning willworker with time to prepare can, in theory, disguise even the most obvious acts of mystic prowess from Sleeping eyes by using Veiling spells. Important to note for the purposes of spell design is the fact that any magical effect intended primarily for concealment of any sort properly belongs to the Practice of Veiling.
While a number of spells stray out from other Practices, the fundamental nature of the Practice does not change. So long as a clouding of perception or manifestation of some falsehood doesn’t directly fall under the purview of another Practice then the spell is a Veiling spell.
In Story:
The secrecy of the Mysteries demands such magics of concealment and misdirection. Many Guardians stress the importance of Veiling magic even more so than Shielding spells: one life is unimportant next to the integrity of the Veil itself.
Even the most retiring Mysterium willworkers and most flamboyant thearchs can find many practical uses for the Practice of Veiling. There are times for secrecy and stealth in research, just as there are times when what a politician conceals is more important than what she shows.
In fact, given the popularity of the Practice of Veiling among Guardians and other secretive sorts, there are those who find themselves distrustful of mages who specialize in such magics.
They wonder if such willworkers have something to hide. To be fair, those who make a habit of going about continually shrouded in Veiling spells usually are hiding something, or else are simply paranoid, neither of which is apt to contribute to their popularity around the Consilium.
Irrespective of whatever stigma may fall upon the Practice of Veiling, however, it remains a popular practice among those mages who understand the importance of stealth and secrecy, or even just the occasional measure of privacy.
Young willworkers trying to establish a place for themselves within the Consilium sometimes find that walking silent and unseen is better for their progress within local Awakened society than any amount of known public service. Likewise, all save the most honest of masters (a rare breed at best) have at least one or two things they’d rather conceal, every now and again.