Mystic Veil

Illusion
Skill Check: Knowledge (arcane lore) DC 34, 7 successes
(and see text); Failure: Two consecutive failed skill checks; Components: V, S, M (see text), B; Casting Time: 70 minutes (minimum); Range: 55 ft.; Effect: Visual and audible figment that covers 12 10-foot cubes (S); Duration: 12 hours; Saving Throw: None or Will disbelief (if interacted with) (see text); Spell Resistance: No
This incantation combines several elements to create a powerful protection from scrying and direct observation. When casting the incantation, you dictate what will and will not be observed in the incantation's area. The illusion created must be stated in general terms. Once the conditions are set, they cannot be changed.
Attempts to scry the area automatically detect the image stated by you with no save allowed. Sight and sound are appropriate to the illusion created. A band of people standing in a meadow could be concealed as an empty meadow with birds chirping, for instance.
Direct observation may allow a save (as per a normal illusion), if there is cause to disbelieve what is seen. Certainly onlookers in the area would become suspicious if marching soldiers disappeared at one point to reappear at another. Even entering the area does not cancel the illusion or necessarily allow a save, assuming that hidden beings take care to stay out of the way of those affected by the illusion.
Options: You can create the material component for the mystic veil illusion yourself at no cost. If you do, the incantation also requires a successful Craft (visual arts) check (DC 34).
Material Component: Realistic paintings, digitally-altered photos, or other representations of the desired illusion (purchase DC 17).
Backlash: Caster takes 2d6 points of damage.
Failure: Delusion. The caster and anyone else present at the conclusion of the incantation believe the mystic veil is effective, but no one else is fooled.