Reply #5: Urethane would help preserve it yes.

[MindPilot]

But let the latex cure for a couple weeks before you try that, and as always test on a hidden place to make sure there's no reaction.

Here's something you may want to try if you want an antique look that will tone down the paint a bit. Go to the art store and pick up a tube of black oil paint. The stuff is kind of expensive so get the smallest tube you can. Or better yet, if you have an artist friend, get a some from them--you only need a tiny bit.

Put a little dab--about the size of a match head--on a rag and rub it all over the piece paying particular attention to the dings and any molding details. Then with a clean rag wipe off the middle of the flat surfaces leaving a little of the oil at the edges. That will accent all the details and dings, giving a real effective antique look. After you do one panel, you see how easy it is to adjust the wiping off part to achieve just the right effect.

Then, once you have it exactly the way you want it, sell it on ebay for $1800. :D