Hi Kathy Do you mean a length of time of thousands of years, when archaelogists might open the grave and find a sealed box with the photo inside? I think you need scientific help, or even an archaelogist might be able to point you in the right direction, just an idea. I've seen headstones with a photo of the people on them, but it's a new idea here. It could be done the way the Ancient Egyptians did theirs, drawings on the wall, then enclosed. There might be a better way, instead of using a paper photo, use tessera. Then paint the picture of the lady on the tessera surface, and if it gets broken, then the pieces can be put together and a face will be revealed. The tessera can be placed in a sealed box, which should protect it's colours. The Greeks and Romans made floors etc., as you probably know and we see their work today. :) Ask a Stone Mason what type of glaze is used. Cheers Dig