Inconsistent timezone offset in PDF CreationDate across pdfTeX, XeTeX and LuaTeX
0 reputation · 23 Nov 2023, 23:48 UTC
The goal is a reproducible date and time representation in LaTeX documents that remains comparable across machines, engines and regional settings.
The LaTeX kernel provides no timezone-aware primitives. \today and \time reflect the TeX engine’s internal clock derived from system local time without zone information. The datetime2 package’s \DTMnow formats the current date and time but does not apply timezone conversion; it prints the timestamp supplied by the operating system. PDF metadata dates produced by primitives such as \pdfcreationdate and \pdfmoddate include a timezone offset only when the underlying engine supplies it, and pdfTeX, XeTeX and LuaTeX differ in that behavior. The LaTeX3 project has an unresolved design question about whether a future timezone-aware layer should be added to the kernel or remain the responsibility of external packages, with no consensus as of the 2024-2025 releases.
What is the documented engine-specific behavior for timezone offsets in PDF /CreationDate and /ModDate? Is there a kernel-supported way to normalize timestamps to a common reference without external tooling? What is the current LaTeX3 position on providing timezone-aware date primitives?
