Eu cito Wikipédia :
PDF was standardized as an open
format, ISO 32000, in
2008, and does not require any royalties for its implementation.
Intellectual property
Anyone may create applications that can read and write PDF files
without having to pay royalties to Adobe Systems; Adobe holds patents
to PDF, but licenses them for royalty-free use in developing software
complying with its PDF specification.
As associações de PDF definiram dois padrões ISO para PDF:
ISO 32000-1 (PDF 1.7)
ISO 32000-1 is the first ISO specification for PDF. The document is an
ISO formalization of Adobe’s own PDF Reference 1.7, and is technically
identical to the Adobe document.
As with previous versions, Adobe’s PDF Reference, PDF 1.7 was (and
remains) freely
downloadable
from Adobe.com (as is the document’s errata). By special arrangement
with ISO, ISO 32000-1 is also available at no
charge
from adobe.com.
ISO 32000-2 (PDF 2.0)
Unlike previous PDF specifications, however, PDF 2.0 is an open
standard. Any subject-matter expert whose country is a member of
ISO’s TC 171 SC 2 can join
the other experts at the table, and help determine the nature and
direction of the world’s de facto electronic document format.
A primeira especificação (PDF 1.7) foi aberta ao público pela Adobe
e é gratuito para download, até mesmo para download do ISO.
A segunda especificação (PDF 2.0) foi escrita por membros da ISO,
então precisa ser comprado para fazer o download.
Como um argumento decisivo, o
Usuário final do SDK do Adobe® Acrobat® Contrato de Licença diz:
Adobe has a number of patents covering technology that is disclosed in
the Portable Document Format (PDF) Specification, version 1.3 and
later, as documented in PDF Reference and associated Technical Notes
(the "Specification"). Adobe desires to promote the use of PDF for
information interchange among diverse products and applications.
Accordingly, the following patents are licensed on a royalty-free,
nonexclusive basis for the term of each patent and for the sole
purpose of developing software that produces, consumes, and interprets
PDF files that are compliant with the Specification:
U.S. Patent Numbers:
5,634,064
5,737,599
5,781,785
5,819,301
6,028,583
6,289,364
6,421,460
In addition, the following patent is licensed on a royalty-free,
nonexclusive basis for its term and for the sole purpose of developing
software that produces PDF files that are compliant with the
Specification (specifically excluding, however, software that consumes
and/or interprets PDF files):
U.S. Patent Number:
5,860,074
Estas são as únicas patentes em PDF, ainda mantidas pela Adobe,
que os liberou para uso público livre de royalties, que inclui
o ISO como membro do público.
No entanto, a Adobe permanece como o único detentor da patente.
Eu também consegui encontrar as primeiras páginas do
Especificações do formato PDF 2.0 ,
que contém um aviso de direitos autorais:
© ISO 2017, Published in Switzerland
No entanto, esse documento também tem este parágrafo:
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will
be in the Introduction and / or on the ISO list of patent declarations received (see www.iso.org/patents).
Eu baixei esta lista de patentes que podem afetar este documento,
e noto que nem um deles pertence ao ISO.
De fato, a ISO não solicita patentes, apenas publica padrões.
Portanto, a situação é atualmente: a Adobe detém patentes gratuitas para
uso público. ISO publicou um padrão para PDF 2.0
que é um superconjunto do padrão PDF 1.7, então ainda está sujeito a esses
patentes.
Conclusão: A ISO detém os direitos autorais do documento, mas não as patentes.