Accepted Evidence Hierarchy

How this page reasons

Purpose: estimate a postcard's production period (its age), not its mailing date.

Primary production evidence (highest weight)

• Back layout
  • Undivided back → upper bound: printed no later than the country's official divided-back acceptance year.
  • Divided back → lower bound: printed no earlier than the country's official divided-back acceptance year.
• Postal wording (country-specific) provides a production constraint based on documented official introduction (used as a lower bound).

Secondary production evidence (supporting)

• Printing technology (Collotype, Lichtdruck, Bromsilber, Real Photo) supports an estimate but does not override primary evidence.
• Illustrator name: informational only. Artist identification does not determine production date and may include later reproductions.

Usage evidence (informative only)

• Stamp issue year: indicates the earliest possible usage, not production.
• Postmark year: confirms when the postcard was mailed. A postcard may have been printed years before use, or reprinted later in the original layout.

Important reminders

• Usage does not override production evidence: a postcard mailed in 1910 could have been printed in 1900 and kept as stock, or it could be a reprint from 1920. Official layout and terminology constraints remain the most reliable indicators.
• Reprints may replicate older layouts: nostalgic reprints from the 1920s or later often re-use older back layouts or wording.
• Country selection matters: divided-back acceptance was not simultaneous worldwide (e.g., France 1904, UK 1902, Germany 1905, USA 1907). Selecting the correct country refines your estimate.

Quick Reference

Official divided-back introduction dates

Below is a core list of official acceptance years for divided backs. If your postcard's country is not listed, refer to UPU historical records or specialized literature.