No question about it. But I wasn't writing what should be but rather what often happens. I was not trained as an interpreter, so perhaps I am unaware of the catches the professionals may have.
Well, there are many catches of course, but the basic rule, be it translating or interpreting, is always the same: translate the meaning and not the words, and it stands even on the level of "good morning" and "how are you". Different languages use different words to convey the same semantic content, and using bilingual dictionaries to check up single words you are likely to end up with phrases like the famous "thank you from the mountain". It's true that it happens often and not only at the beginner level, and this is exactly the reason why I think that bilingual dictionaries can be more of an obstacle than a helping tool. It's much easier to render anything properly using monolingual dictionaries which show you how a word "works" in the language.
Bilingual dictionaries have their uses but they should not be over-used and certainly shouldn't be the only translation tool.
Strangely though, I find it easier to translate from my native Polish to English, which is my second language, but I feel that, without prior preparation, some texts would simply be not interpreted properly from one language to another.
You've been living in an English-speaking country for many years so it might be that Polish has been pushed a little to the back of your mind and you find English phrases more readily available. This would probably reverse if you spent a couple of months in Poland.
As for the preparation, I'm not sure what you mean, but certainly you must know what you're talking about - I mean, understanding of the subject matter is absolutely necessary, you can't translate/interpret anything that you have no idea about, even if you are brilliant in both languages.
a seasoned translator, such as ourselves in our respective languages, should and IS able through thorough training, to "switch gears" and not only translate into as well as from the source language, but into and from a variety of disciplines too, for example business and law. Both are related, as opposed to gastronomy and metaphysics or some such nonsense:-)
I'm not sure about the translating "into as well as from the source language". Many good and seasoned translators work one way only, even if their command of the second language is close to native or even if they come from bilingual families but were raised in only one of the respective countries. I'm not talking about interpreting simple conversations or translating family letters, but of the work one is doing as a professional.
It also depends on the specialisation field, it's possible to work both ways with finances, medicine, law or engineering, but very very few people would be able to translate both ways things like literary essays, not to mention literature as such.
Neither is a variety of disciplines any proof of the translator's seasoning and worth. The worthy and seasoned ones know their limits and don't try to tackle areas they don't know the first thing about. Business and law often go hand in hand, it's even possible that a law translator is a passionate cook and therefore able to handle gastronomic translation, but expecting him to know metaphysical concepts and vocabulary could be too much. The best ones often limit themselves to one field and do just law, or just medical.