On a perfect bound or double loop cover, you may print the entire area of thespine, but be sure to consult with us beforehand. You’ll need to measure the spine using a bulking dummy to be sure of the exact width. Ink coverage that traps to scoresor bleeds across the spine will also need close attention to ensure proper registrationand to avoid cracking. In addition, perfect bound books will need four scores on the cover [two backbone plus two hinge] for durability and to protect any glued areas when opening. The paper you choose is also a consideration for perfect boundbooks; text and cover pages must be parallel with the spine or the covers may wrinkle.