I think some law was passed in the last year that requires all photo apps to come with filters that function as aesthetic time machines, passing your perfectly fine photograph through a wormhole of analogue nostalgia. It turns out that creating such a rift in photographic spacetime is not as easy as sending your photo through it.
The makers of Camera+ have documented the process of creating a filter, and it's a bigger pain in the arse than dealing with vinyl. Filters are created in Photoshop, tested against hundreds of photos, tweaked, re-tweaked, texturised, finalised, coded, optimised and then finally shipped.
Faaarrrrrrr ouuuuuutttttttt. [Tap Tap Tap]