Tras vs detrás

Question

Que tal,How interchangeable are tras and detrás? Is one preferred over another, and if so, does it vary by country or age or context?I'm think about basic use meaning 'behind,' such as "El niño se escondía tras (detrás) las cortinas."Thanks!

Accepted Answer

Hola Christian
tras and detrás are synonyms but used slightly differently. You need "detrás de ..." but you don't need "de" with "trás". So your sentence would be either:

El niño se escondía detrás de las cortinas.
El niño se escondía tras las cortinas.
The kid was hiding behind the curtains.

Tras is slightly more formal than detrás de. Kids for example wouldn't normally use tras. Tras is seen more in formal written Spanish. 
We can also use detrás as such (with no de), but this is only if there is no noun after it, for example:

Pon eso detrás, no delante.
Put that behind, not in front.

In this case we cannot use tras, we always need tras followed by a noun or a pronoun:
tras la ventana, tras las cortinas..., tras ellos... etc
I hope this clarified it.
Saludos
Inma

Answer

Thanks, Inma! That was an awesome answer and it definitely helped!