A: Great Question! The Scotch Permanent Double Sided Tape is photo safe because it passed the Photographic Activity Test, widely known as the PAT, in an International Standard - ISO 18916. The Photographic Activity Test (PAT) is an industry-standard test that uses fading, spotting or staining detectors to evaluate whether enclosure materials, inks and adhesives are safe to use with silver photographic images. As of 1997, this test is done on negatives, as well as the fronts and backs of both color and black & white photographic prints. Products which pass this test will not damage or change the image on negatives or photographic prints. 3M has this testing done by an independent laboratory. We hope this helps!