When is it "noun adjective" and when is it "adjective noun"?

[samcanning]

I've seen phrases like "oiseau rouge" for "red bird" but I've also seen phrases like "noire robe" for "black dress". What determines whether the adjective comes before or after the noun? Is it the sentence structure? The gender?

[Sitesurf]

In 90% of cases, the adjective is placed after the noun in French. For other cases, please read this:
http://french.about.com/od/grammar/a/adjectives_4.htm

[samcanning]

Thank you!