Photographic envelope enclosures in U-style, made from transparent archival paper without an alkaline buffer. The envelope opening is on the longer side. Suitable for archiving photographs, negatives and glass slides. Other sizes available upon request. Both, the paper and glue have passed the Photographic Activity Test (PAT) in accordance with ISO 18916. Available sizes: 9x13 cm 10X15 cm 13x18 cm 18x24 cm A4 30x40 cm A3