Quality requirement of hardback finished products:

Clear surface, no obvious warp,standard four corners of the book,qualified square,normative round back, clear pattern and stamp words of book cover, non-tinting, firm and good gloss.
Error of foil-stamp is in accordance with specification.
Clean and firm joint, the depth and width is about 3.0 mm±1.0mm..
Back and front of circular endpaper and book block has no obvious wrinkles.
The entire words error on the back bone is less than or equal to 2.5mm.