I'm doing a little experiment. NOTE: this technique is not recommended for scrapbooking. The other day I was helping my kids do a Nativity stained glass window using oil. And then I got an idea. (We'll see how bright it is a few days from now.) I'm oiling paper to give it a translucent look, which kind of mimics vellum. But my method is much cheaper thus far.
So the first picture is my stamped images on white cardstock. (Use thinner paper for more translucence. Prolly 24 lbs. paper would be nice.)
Stamp your images as you'd like them to appear. You can use black ink, watercoloring or whatever.
The second picture shows that I flipped the images to the back side of the paper, because we're going to oil it from the back. It reduces any chance of ruining the image. Place image face down on a Viva paper towel. Now pour some vegetable oil over the paper and rub it in with a wadded paper towel or cotton ball.
In the last picture you can see that the wrong side of the images are a muted version of the original.
Place your oiled paper in between two layers of paper and then paper towels and let sit under a heavy book for a day or two. The oil *should* all get absorbed so that you can use it for card making. I'll post my results in a few days so we can see how my little experiment worked.
I'm thinking that you could oil a sheet of paper and then stamp on it with craft ink, too.
*My kids' stained glass window pictures set on paper towels for two days and are now hanging on a window with no oil marks. I'm keeping my fingers crossed.