Mainly used for collectible books, art albums, commemorative albums, high-end portfolios, yearbooks, gift books, cookbooks, etc.
Inner pages are generally sewn into a book block, or can be perfect bound into a block; a hard cover is made separately (grey board + paper / cloth / specialty leather wrap), and then the book block and hard cover are connected and fixed through endpapers. Divided into rounded spine hardcover and flat spine hardcover.
The shell is rigid grey board, stiff and wear-resistant, highest grade;
Rounded spine: the spine can be made into an arc; flat spine: flat and straight hard spine;
Has endpapers (blank lining paper between the cover and inner pages);
The book is thick and heavy, with strong protection;
When opened: sewn book blocks can mostly open well.
Page count: wide range, from dozens of pages to over a thousand pages;
Cover material: 2.0–3.0mm grey board, surface wrapped with art paper / specialty paper / cloth / PU leather;
Advantages: high-end texture, durable, strong preservation;
Disadvantages: expensive, long production cycle.
