Long term storage of large prints?

How would you suggest storing large prints, 12 x 18, or 16 x 20, without having to roll them? Need to put some away for a long period and don't want them to deteriorate.

you can find boxes like these...
http://www.lightimpres​sionsdirect.com …flat-photo-storage-boxes/

Light Impressions was a great company 20 years ago, but current management seems to be a bit flakey according to more recent feedback on the web, so you might well wish to go with a different brand!

Storage and Care of KODAK Photographic MaterialsBefore and After Processing

Thanks. I'll look into storage boxes.

You did not say if you printed yourself or not. If you do, simply save the paper boxes and store the prints back into them. I separate each print with a sheet of paper. For that, you can buy a roll of craft paper or buy a large artists sketch pad. If you're printing from rolls or sourcing printing, you'll have to buy the boxes.

Call up Bill Gates. He built a storage container inside a mountain in Colorado where he stores historic and original prints, photos, film, posters, ... probably his personal porn stash, his blood, DNA, etc.

Otherwise, a safe at a bank, or any storage unit will do.

Store the digital copies so you can reprint them in better quality decades from now : D

I have the prints. I did not print them. There are no digital copies of these prints.