Old Photo paper, background texture yellowed and notched, from a vintage photo album
"Photographic paper is a paper coated with a light-sensitive chemical formula, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from fixing and clearing, though latent exposure is also usually present."Wikipedia, The Free Encyclopedia, "Photographic paper", https://en.wikipedia.org/wiki/Photographic_paper