It is our understanding that there are currently no regulations relating specifically to pressure sensitive label materials being used in archival applications, like labeling books and photos. The facestock of the Standard White Matte (WX) complies with the NSI/NISO Z39.48-1992 for "Permanence of Paper for Publications and Documents in Libraries and Archives". Claiming that any adhesive is definitively safe for archival purposes is difficult, due to the fact that there’s no accurate method of measuring the acidity of an adhesive once it’s been applied to a label product. The OL5100WX utilizes an emulsion acrylic adhesive rather than a rubber-based adhesive, making it better suited for archival applications. Emulsion acrylic adhesives do not yellow or degrade to the level that rubber-based adhesives do. The adhesive is also water based and does not include any of the oils used in the compounding of rubber-based adhesives. In addition, the adhesive has passed the Photographic Activity Test (per ISO-18916), which specifies that it is compliant and graded for use in photo-storage applications. If you have any other concerns or questions regarding the materials, you're welcome to reach out to Customer Support at 888-575-2235.