What Faith Up/Down and Evil Up/Down Does?

[D.A.R.K.]

First, sorry for bad english, I'm from Brazil.

Almost all runs I do, there's some items giving me Evil Up and Faith Up and I don't know if it useness or not, I just pick it up cause I can. Anyone can tell me what Faith and Evil does and if there's any problem taking both buffs, if it's better be more Faith or more Evil or both or I don't know....

[unlucky]

it increases chances of devil/angel rooms that as much as i i really know (and probably sacred/evil hearts)

[Kinne]

It lets you search the wiki

[D.A.R.K.]

Ursprünglich geschrieben von Kinne:

It lets you search the wiki

Good, now tell me about lose your time doing a useless stuffs like that...

[D.A.R.K.]

Ursprünglich geschrieben von unlucky:

it increases chances of devil/angel rooms that as much as i i really know (and probably sacred/evil hearts)

Thanks.

[1337Walrus]

evil up = Black hearts spawn more often, Angel Rooms spawn less often.
faith up = soul hearts spawn more often, devil rooms spawn less often.
Not sure if Eternal hearts check faith/evil.

[Doniazade]

Faith and evil are not actual stats though, they are just the game's way of saying the item does the above. There's no faith stat in the game's memory that is incremented by Bible Tract etc.

[Dagger]

Ursprünglich geschrieben von Doniazade:

Faith and evil are not actual stats though, they are just the game's way of saying the item does the above. There's no faith stat in the game's memory that is incremented by Bible Tract etc.

Wiki: Increases the chance of finding an Angel Room and also affects Soul Heart drops. The higher the faith, the higher the chance of finding Angel Rooms and Soul Hearts. Also increases chance of finding Eternal Hearts

So the items are additive, thus the game is keeping track of faith increments.

[Doniazade]

I am perfectly aware of that, I am just saying that there isn't an actual stat in memory called Evil or Faith.

http://www.reddit.com/r/bindingofisaac/comments/2nnc1e/detailed_stat_changes_for_every_item_in_the_game/

So you can't quantify it as saying that the items e.g give +2 faith, but rather the items give +whatever% soul , +whatever% eternal and +whatever% angel.