Photo storing question

[thecatspajamas]

If you're going the backer board route, comic book and magazine backing boards come in a variety of sizes and are typically manufactured to be acid-free. There are also "buffer" sheets that you could place between the photo and board if you want to go the extra mile for preservation.

I would recommend going with "collector's supplies" that are held to higher standards, typically stated on the packaging, rather than the cheap multi-pack of something from the stationary department of your local big box store though. Those stationary/printing products may look great now, but most are not manufactured with long-term archival storage in mind and may do more harm than good in the long run.