Paperboard Thickness

The paperboard thickness of the cover determines how thick the book cover (often called MGP = machine grey paperboard) will be.
The strength selected can and should vary according to the number of pages in the inner part. A few pages with a thick envelope can easily appear overdone, while many pages with a thin cover can lead to a print product with a poor grip.

The paperboard thickness affects the first impression a book makes.
Raw and slightly thicker grey paperboard is used by preference, for example, for the stiff soft cover.