When you create a document with perfect binding (also known as glue binding), the cover requires a spine, i.e. the outer portion of the document which covers the actual binding.
Basic characteristics for a Perfect Bind Brochure
Gelato supports perfect binding between 28 and 250 pages. The spine area for a document design depends on:
Number of pages
Paper type (Coated / Uncoated)
Weight of the paper
E.g. Below is the spine calculation for an A4 multipage brochure of 72 pages with 250 gsm silk paper cover and 170 gsm silk paper for the inner pages.
The file you submit should follow these guidelines:
The cover is designed as a spread (including the back cover, spine, and front cover)
The cover (exported as a spread) is page 1 of your PDF file
The Inner pages come after the cover and should be exported as single pages
Practical Example: 32-page perfect bind brochure
The PDF file's page count should be 31 (the back cover and cover will count as 1 page). This is due to the fact that the cover will be exported as a spread, while the inner pages will be exported as single pages.
This is the overview of how the PDF file should look like:
Calculating the spine
Minimum Cover Width (1st page in the multipage brochure PDF) = Bleed + Back Cover Trim Size + Spine Width + Front Cover Trim Size + Bleed
Example calculation for width of 210mm x 297mm cover with 60 inner pages = 4 + 210 + 3.429 + 210 + 4 = 431.429 mm
Minimum Cover Height = Bleed + Book Height Trim Size + Bleed
Example calculation for height of 210mm x 297mm document cover = 4 + 297 + 4 = 305
Download an example here.