Gutter / creep (shingling)
The gutter keeps content out of the binding; creep is the outward page shift in a thick folded booklet that makes inner pages lose outer margin.
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What it is
Gutter and creep solve different binding problems. The gutter is extra space at the inner edge so text and faces do not disappear into a fold, glue line, or punched binding. Creep, also called shingling, is the outward push that happens when folded sheets nest inside one another in a saddle-stitched booklet.
The thicker the stock and the more nested sheets, the farther the inner pages protrude at the fore edge. When the booklet is face-trimmed, those inner pages lose more outer margin. Creep compensation shifts their page images progressively toward the spine before imposition so the finished margins look steady.
Gotcha: adding one large gutter to every page does not compensate for creep. Gutter belongs in the page design; creep belongs in the imposed printer spreads and varies sheet by sheet. Get the bound stock caliper and finishing method before calculating either one.
Ask AI for it
Prepare this saddle-stitched booklet in Adobe InDesign. Set a binding gutter that keeps live content clear of the fold, then use Print Booklet's Creep value with the confirmed stock caliper to compensate each nested sheet progressively toward the spine. Return a table of sheet number, page pair, creep offset, inner margin, and outer margin, plus an imposed PDF proof with the center signature and fore-edge trim clearly marked.