How do you distinguish "trademark" and "registered trademark" in Spanish?
In English, there is a difference btwn "trademark (TM)" and "registered trademark (circled R)". Is this the same in Spanish? If "trademark" is "marca registrada", then how do you actually emphasize on the fact that it has been registered through a proper authority, and not anyone simply claiming that it is?
I'm afraid that I don't know the answer to your question off the top of my head. However, you might be interested in having a look at the website of the Spanish Patents and Trademarks Office. It is www.oepm.es and most of it is available in English (see top right for "Welcome" sign).
If I discover anything more definite, I'll come back to you. However, it is likely that someone else may be able to provide the answer for you.
To answer your question: to let it be known that a logo is a registered trademark, you'd need to show the rabol (circle "R"), which would be a «marca registrada». "Trademark" is not, in my opinion, «marca registrada», but «marca de comercio».
I have no official documentation for my response, but I would imagine that they would be differintiated by one being «marca de comercio» (comerciante/comercial) for "trademark", while the otherwhich is registeredbeing «marca registrada».
My reasoning being that "trademark" simply means a mark of trade, regardless of it's registry status, that is, una marca de comercio no registrada (unregistered trademark). While the rabol (circle "R") is registered, that is, una marca registrada (registered trademark).
I have also looked for this information and have found very little on the subject... I have seen the rabol on many spanish logos, but have seen the absence of any trademark marking just as often. As far as I can guess, if the logo or logotype is distinct enough and specific to a particular company or it's services and/or products but remains unregistered, there is little trouble to expect from it so long as there exists a long standing good reputation from the logo and company which can be readily identified by the public, which would be used in court to establish damages or the like from would-be impersonators who attempt to ride on the coattails of the logo. Regardless, I am not a lawyer, and would strongly advice you to seek proper legal council before entering business and not simply take my word for fact.
Hope that helped.