Seoul summers push relative humidity above 80% for weeks. Holders who laminated seed phrase sheets in 2018 often discover edge curling by the third season. The laminate traps moisture against paper rather than protecting it.
What we observe in sessions
Peeling corners expose adhesive lines that confuse OCR attempts—irrelevant for offline holders, but the physical damage is real. Ink underneath can smear when condensation forms between layers. Metal plates stored in the same drawer fare better, yet clients forget which plate corresponds to which wallet generation.
Materials we recommend instead
Acid-free envelopes with pencil markings on the outside only. Reference codes written on tabs, not on the phrase sheet itself. Silica gel packets replaced every six months in home safes without climate control. For coastal properties in Busan or Jeju, we suggest double envelopes with desiccant between layers.
Ledger cross-reference
When we catalog laminated sheets, we note lamination date and condition grade (A–C). Grade C sheets trigger a conversation about re-copying onto fresh archival paper during a controlled session—you transcribe, we witness placement, we never retain copies.
This note supports physical backup care. It does not address wallet software, exchange accounts, or asset allocation.