Manufactured in the UK by Conservation Resources, these negative envelopes use our Silversafe® 100% rag, pH 6.0, non buffered 120gsm sulphur and lignin free paper. We use our neutral pH starch adhesives throughout. Envelopes are hand-made with one side and bottom seam only. This product opens along the short side. This quality has passed the PAT test. Available in packs of 50, 500 and 1000 envelopes.