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 or 500 envelopes.