Yupo is a type of nonporous paper used with alcohol inks. Unfortunately, it is costly, especially if you just want to use it for experimenting. I've heard of using photo paper, but I had just given my stash away. *Sigh*
I decided to try to make my own paper out of stuff I had already bought.
I brushed some Liquitex Gloss Medium & Varnish over some cardstock.
It didn't take very long to dry and created a nice gloss effect on the paper. You can definitely see the brush marks, which could be used to advantage if you want more texture in your design.
It also tends to make the paper warp a bit.
Despite these possible flaws, it did work well with the alcohol inks.
Top Right: one of the treated papers with Piñata inks.
Bottom right: a treated paper with homemade inks. They are a little more transparent.
Left: a sheet that is not treated. On the top are the Piñata inks. On the bottom are the homemade inks.
Verdict: They worked great! You can't really see the brush marks once the ink is on, but that might be due to the colors I used.
The curling paper could likely be fixed by sticking it in a heavy book when it's try to flatten it out.