koperta

Koperta is a flat, paper-based container designed to enclose letters and documents for mailing. It protects content, facilitates handling by postal services, and provides privacy by concealing the contents. Most koperty are made of paper or light cardboard and use a flap that is moistened or self-adhesive to seal the envelope. Some varieties include a transparent window (koperta z oknem) to display the recipient’s address printed on the letter, while others focus on security with reinforced seams or inner linings.

Koperty vary by construction and purpose. Closing methods include moisture-activated gummed flaps and self-adhesive seals. Special types include koperty z oknem (with window) and koperty bąbelkowe (bubble-lined) used for cushioning small items. Security-focused envelopes may feature tamper-evident designs or opaque interiors. Materials can range from standard white or colored paper to recycled content, and some are reinforced for heavier documents.

Common sizes follow international standards. Typical formats include DL (approximately 110 × 220 mm), C6 (about 114 × 162 mm), C5 (162 × 229 mm), and C4 (229 × 324 mm). These sizes align with standard paper formats and common postal requirements, with A4 documents often folded to fit.

Etymology and history: the term koperta is native to Polish and the envelope as a mailing container emerged in Europe in the 18th–19th centuries with advances in paper production, adhesives, and mass mailings. Since then, koperty have become widespread in personal, business, and administrative communication.

Environmental considerations: most koperty are recyclable, especially those made from uncoated paper. Some variants with plastic windows or bubble linings may require separate disposal.