Our alcohol-ink-on-plastic-paper lady has done more lovely originals. Those I framed a few years ago were all two-pieces, alcohol ink on synthetic paper, which I hinged meeting in the middle, to give the same affect a 'Rorshach' drawing has. I told her at the start that, because nothing was holding the center edges down, they might ripple up over time, which has happened a bit. She still likes them, but not an ideal treatment. After that batch, I told her that, for works on single sheets of plastic paper, some people mount it to a substrate prior to painting, so they don't have to hinge later. Couldn't figure out how to mount her already-painted two-pieces, though. Now, she's made more of the two-piece mirror-image paintings, and is interested in mounting, rather than hinging, so there's no risk of the centers rippling up. She suggested using a tape or gel of some kind, and I told her any tape need to be both temperature-tolerant and not damage her art. Because it's plastic sheeting, it wouldn't react like paper to heat changes, but I know that plastic still expands and contracts some. Also, whatever we attach it to might do it. Using a gel (acrylic maybe?) is imaginable for the first half, because any that squishes out at the center could be wiped away, but for the second half, we wouldn't want excess squishing onto the other side of the piece. If she did find a tape that worked, because it's not paper, I'm wondering if she could just run a strip (or two) down the middle and on the outsides, but if the current centers have rippled up a bit over time, it seems there might be some weirdness between the part of the sheets that has tape underneath and those that don't. Lastly, I used a magnifying glass to position her first ones for hinging, and I've told her that something that grabs right away and can't be re-positioned wouldn't be good if we had to adjust. Each half is 5 1/2 x 14", vertically oriented, so the whole result will be 11 wide by 14 high. Thanks for reading all this.