For official purposes, translations are done by a translator sworn before the courts according to the Sworn Interpreters and Translators Act (Wbtv) in The Netherlands. Examples are: deeds, contracts, articles of association, documents and official documents issued by local government and also an adoption certificate or a will.
These are translations provided with a statement by the translator, indicating that the translation is a true representation of the original. Swearing does not necessarily add any quality to the translation. A sworn translator does comply with the requirements of the Register of sworn interpreters and translators.
Basically a sworn translator is entitled to do certified translations for the translation combination(s) for which he is listed in the Register. If a translator is registered for the certification from Spanish to Dutch, he shall only authenticate documents drafted in Spanish and translated to Dutch. A translator may be sworn in by a Dutch court for a combination of two languages, for example, from German into Spanish.
Polydioma of course provides, if necessary, in addition to certification, an apostille for your translations and, where appropriate, also looks after the legalisation of your document.