If you're like me and are unfamiliar PnP Blue Transfer Film, it's basically an acid resist used when etching metal. It's sold in 8 1/2" x 11" sheets that can be put into your laser printer. This remarkable feat lets you photocopy ANY IMAGE onto the sheets thereby producing very detailed images. You then apply the sheets to your surface and etch away. But that's not where the coolness ends! Etsy contributor daniellexo decided to use PhP to etch glass, and it worked marvelously. Take a look:
The image is that of Martha Stewart, the quote from the big M herself. To see how it's done, visit this page on Etsy.