At what level do items start producing higher-tier crafting materials? [duplicate]

Question

Possible Duplicate:
How do I find items with the right level to salvage particular ingredients?

There are four tiers of crafting materials, one for each difficulty level. At what item level do salvaged items start producing materials of a higher tier?

I've seen people claim you start seeing Nightmare materials at level 30 and Hell materials at level 50, but I've found evidence that Nightmare materials show up as early as level 27, but not for every item type.

What's the real answer here? Also, what about Hell and Inferno?

Answer 1

Each item simply produces whatever the developers decided that it should. The type of material is based on the difficulty in which you would most likely find the item. In regards to the items mentioned that produce materials for a seemingly higher difficulty, this is because those items would typically be found in Nightmare, even though they are below level 30.

Answer 2

The crafting materials aren't based on the item's level - they're based on what mode it dropped in.

There's some level overlap between Normal and Nightmare, since not every player will reach the same level by finishing Normal. This means that you'll get Nightmare-level materials from some items (like the level 27 ones mentioned in the questions) that are lower-level than level 30 items dropped in Normal.