The supplies are simple: Inexpensive white glazed tiles from your favorite home improvement store, Adirondack Inks from a craft store which are a little pricey but go a long way, and some type of clear water based finish are all you need.
I will link you to a website with all the info you need because I don't want to take credit for someone else's idea. However, before you leave me let me tell you how hard it has been to clear coat and protect these precious pieces of artwork. Once you have read her post make sure you skim through all the comments about finishing. Because the inks are alcohol based you must finish these art tiles with a water based clear coat. Well, silly me thought brushing on water based polypropylene would be the best approach (this was before I read all the comments). The inks are so delicate that the brush scratched and/or moved the ink in the direction of the brush. I tried pouring it on, and though this worked best, it still "pocked" some of the most vibrant colors or made them run in the direction I tilted the tile to get the best coverage. My boys are still mad at me for messing up some of their pieces and my husband won't let me near his work at all. There are spray alternatives out there, but I haven't found one in a local store yet. If you read the comments in the site I was working from, there were issues there. Once I find a spray to use I imagine it will take many very thin coats sprayed from very far away.
One other comments is to remind you to stay light with the ink. My young boys just loved these inks and used way to much which is apparent by the over abundance of brown and black on these tiles. However, My favorite one ended up being my son's blackish tile near the top right of the picture above. Go figure.
So here is the link to the website that inspired me and has led to some terrific family time.
Artsyville by Aimee