Photo book print specs: bleed, resolution and what a print shop needs
A print shop needs a PDF of the inside pages with 3 mm of bleed on every side, photos at about 300 pixels per inch, fonts embedded, text kept at least 6 to 8 mm from the edge, and a separate cover file with the back, spine and front on one sheet.
Bleed: 3 mm on every side
Printers cut pages after printing, and the cut is never perfect. Bleed is extra picture that runs past the edge of the page so that a slightly-off cut does not leave a white sliver. The usual amount is 3 mm on each side.
A photo that touches the edge of the page has to extend into the bleed. A photo that sits inside a margin does not.
Safe margin: keep words 6 to 8 mm from the edge
The same imperfect cut can also eat into the page, so text and faces should stay a little way in. Keep them at least 6 mm from the trimmed edge, and 8 mm on a hardcover book.
On a book that is glued or sewn, the middle of each spread disappears into the binding. Keep text 10 to 12 mm away from the fold, and do not put a face across it unless the book is lay-flat.
Resolution: aim for 300 ppi
Resolution on paper is pixels divided by printed inches. A photo 3,000 pixels wide prints at 300 ppi when it is 10 inches wide, and at 150 ppi when it is 20 inches wide.
At 300 ppi a photo looks as sharp as the print can be. Down to about 220 ppi most people cannot tell. Below 150 ppi it looks blurry. If a photo is too small for its frame, make the frame smaller or use a different photo.
Page count depends on the binding
- Hardcover and softcover: 20 to 200 pages, in twos
- Lay-flat: 10 to 100 pages, in twos
- Stapled booklet: 8 to 64 pages, in fours
These are the limits Tadabook uses. Ask your print shop for theirs, since paper and machines differ.
The cover and the spine
The cover is one wide sheet: back cover, spine, front cover, in that order. The spine’s width depends on the page count and the paper, so any number worked out in advance is an estimate. Ask the shop to confirm it before printing. A very thin spine (under about 4 mm) has no room for text.
Colour and fonts
Send photos in sRGB unless the shop asks for something else; digital presses and photo labs expect it. Embed every font in the PDF so the text prints exactly as you saw it.
How Tadabook handles it
Tadabook builds the files to these numbers for you: 3 mm bleed with trim and bleed boxes, photos prepared at 300 ppi, embedded fonts, a one-sheet cover, and a spec sheet to hand to the shop. Its print check flags any photo under 150 ppi, text that does not fit, text too close to the edge and a page count the binding cannot take.