I have some drinking mugs that can hold artwork in the liner. I have just the mugs, not any pre-printed art. The artwork template (here is the PDF) states
After submission of artwork, art will be arched 12 % for curvature.
I understand that is to compensate for the tapered shape of the mug - I assume this will change the art into a trapezoidal shape. What does the 12% mean? Is it the ratio of the width at the top and the bottom (i.e. the bottom is 88% the length of the top) or something else?
Using Photoshop or something similar (I have access to Photoshop and Corel Painter Essentials), how can this be accomplished?