This is from an article on Mickey Mouse that was linked to in the original Sherlock Holmes article:

Here is where it gets tricky: Disney also holds trademarks on its characters, including the “Steamboat Willie” version of Mickey Mouse, and trademarks never expire as long as companies keep submitting the proper paperwork. A copyright covers a specific creation (unauthorized copying), but trademarks are designed to protect against consumer confusion — to provide consumers assurance about the source and quality of a creation.

Boiled down, any public domain use of the original Mickey cannot be perceived as coming from Disney, Ms. Ginsburg explained.

Source: https://web.archive.org/web/20221227170631/https://www.nytim...

Out of curiosity, how clear does it need to be presented to the viewer that this is not a Disney production? Does it need to be written out at the beginning "The characters depicted here are entirely fictional and are not from the Disney corporation"? Or can it be at the end credits? Is it sufficient to expect that a viewer seeing the Warner Brothers animation and music at the beginning would know it's not Disney, or does it require more?

As far as I know you can't get out of it by saying "this definitely isn't a Disney product", no matter how clearly.

They try and defend that thing crazy too, I believe deamau5 got in quite the legal battle with his mouse helmet.

Good enough to convince a jury. Which is an unfortunate criteria, but so.

Would you be allowed to sell and distribute the original Disney cartoons? Just can't create any new stuff? (at least on a rolling X years basis?)

Yes (assuming no further bullshit from Disney), in 2024 you would be legally allowed to sell a verbatim copy of the original Steamboat Willie animation, including any bits where it says "this animation was made by Disney" (because that's just factually true). But if you remixed Steamboat Willie into something different, you wouldn't be legally allowed to even remotely suggest that your remix was made by Disney.

That's wild to me... but I guess if it all checks out legally.

I think its only blows my mind because of how hard Disney protects against that sort of thing. I guess they just can't fight it anymore tho.

Trademarks are supposed to designate the source of a product or good--not the good itself--and you have to actually use it in practice. The estate could have probably created Sherlock brand corncob pipes and maintained a trademark. But that wouldn't allow them to block someone from making a Sherlock Holmes movie or reprinting the books.

It might work for Disney because they have real products and can use Mickey to brand them. Even that won't stop someone from making Steamboat Willy 2. But it might block someone from making MickeyLand Amusement park.

My guess is that there is a window of time from creation of a mark during which it must be registered to be valid.

Trademarks don’t stop new creative works. They can only stop misleading use (like using the name to refer to something else).

So if Holmes is trademarked I can’t make “Evil Sherlock Holmes Supervillian Movie” but I could write a story wherein he is his usual self.

I'm not sure that's correct. I think your 'Evil Sherlock' is a perfect example of what is now allowed without copyright protections.

I believe a trademark just prevents you from releasing a new Sherlock narrative that misleads the public that it's a legitimate story from the original collection.