2021.03.02 21:52 "Re: [Tiff] [Off Topic] TIFF trademark", by Bob Friesenhahn
If Adobe were serious about defending their trademark they would have to demonstrate that they engage with people who wish to use it. The lack of engagement which they have demonstrated so far suggests they have abandoned their claims to TIFF.
There is no mention of Adobe trademarks in the TIFF specification, other than for PostScript. There is no mention of a TIFF trademark. The only reference to intellectual property is regarding the copyright and licensing of the TIFF specification text itself.
This would be for a registered trademark. A trademark can exist simply because it is already used for "trade", although it is not registered. A registered trademark offers the holder special powers, although an unregistered trademark may still be defended.
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt