Shouldn't it be "La falda roja esta nueva"? new being a "temporary" adjective and not a constant state?
The rule of temporary versus permanent doesn't always apply. For example, when somebody is dead (quite a permanent situation), we say "Él está muerto".
In Spanish, we say "Él está muerto" because the language comes from a very Christian culture which believes that death is temporary, that we just move on to the "next life".
Why is 'La falda de roja es nueva' incorrect? Isn't this the form of the sentence typically used in previous exercises to assign adjectives to a noun?
You don't use de to assign the color to the noun. That would be like saying "The skirt of the red is new".
But you use it to assign properties regularly - e.g. 'jugo de naranja' - orange juice. Funnily enough, wouldn't this be accurate if you are talking about the fruit or the colour? Just as the equivalent would be in english?
You can think of Jugo de naranja as "Juice of orange". In this case, de means "of" or "made of". Colors don't use this relationship.
Jugo de naranja
Why some adjectives before the noun and some are not. I don't understand the rules regarding adjectives