I use Press-n’-Peel/lazer printer ink image transfer process as a resist for etching my printing plates. I use the Staedtler pens for touch-up purposes when the design doesn’t transfer perfectly. They can also be used for drawing directly on the metal. This ink will hold up longer than Sharpie ink will. I bought a box of ten from Amazon.com at a good price. Update: 2018 I recently switched to salt water etching with citric acid added to the solution and discovered this resist did NOT hold up as well as in the salt solution without the citric acid.