Step 4: Prepare your image
So, pick an image you'd like to etch. In general, you'll want something with high contrast, since , while grayscale will etch, greater contrast looks better. I used a sillhouette picture of me, and it turned out well.
OK, so using your favorite image editor, convert the image colors to grayscale. This will give you a better idea of what the image will look like once it's etched.
Now, scale the image so that it'll print to a fairly small area. Mine were 3"x4", and they worked out alright. I tried a full page image, and it's really hard to get the transfer to work for larger images. Try something small to start out with.
Remember that the image will be flipped (mirrored) when you transfer it, so you might want to flip the image before you print it (and definitely flip any text).
Print the image onto a normal sheet of paper and see how you like it. Play around with it until you're happy. Then, move on to the next step.
You might notice that I made 4 small images. Play around with it! Try inverting the colors, or playing with the contrast/brightness settings