Gussets
Gussets (in printing) are wrinkles or folded-in creases that form in the moving paper web, creating a small “tucked” fold that prints through as a repeating crease/wrinkle defect. The word comes from a “gusset” fold (like in fabric), because the paper forms a little tucked flap rather than a simple wrinkle.
In books, gussets usually show up as:
- A narrow crease line (sometimes doubled)
- Distortion of text/images along the crease
- Repeating marks in the same location across many pages
- Sometimes associated with heavy ink coverage areas, where the gusset is more visible
Consumers often describe it as:
- “A folded-in wrinkle line that repeats”
- “A crease that looks like it was pinched during printing”
- “The page has a tucked wrinkle”
- “The print is distorted along a crease”
Also Known As: Web gussets, gusset wrinkles, tucked wrinkles, web crease, web wrinkling (related), rucks (sometimes), web buckle (related).
In simple terms: the moving paper formed a small tucked fold, and that crease printed into the pages.
What causes gussets?
Gussets are typically caused by web handling problems on roll-fed (web) presses—especially when tension, alignment, or guiding causes the web to buckle and “tuck.”
1) Web tension imbalance
If tension is too high, too low, or uneven side-to-side:
- The web can buckle
- A wrinkle can collapse into a tucked gusset fold
2) Poor web tracking / misalignment
If the web isn’t running straight through rollers, guides, or turn bars:
- The web may “walk”
- Edges can wrinkle and fold inward into a gusset
3) Turn bars and directional changes
Web presses often route the paper around turn bars and rollers.
Directional changes can create:
- Edge stresses
- Buckle points
- Tucked folds if setup isn’t stable
4) Roller/nip issues
Uneven nip pressure, damaged rollers, or mis-set rollers can:
- Pinch the web
- Encourage a tuck fold to form and persist
5) Moisture/heat effects (heatset web)
Heat and moisture changes can alter paper web shape and stability:
- Uneven drying can cause cross-web shrink differences
- The web can become less stable and more likely to wrinkle or tuck
6) Paper roll quality
Roll defects in the cover stock or interior roll can contribute, such as:
- Uneven winding tension
- Telescoping
- Edge damage
- Caliper variation
These can create tracking instability and wrinkles that evolve into gussets.
How to identify gussets in a book
What it looks like
- A distinct crease line that may look like a “pinched” fold
- Distortion of print along the crease (stretched, broken, or uneven)
- Sometimes the crease has a slightly doubled appearance because it’s a tucked fold
- May create a narrow band where ink density looks different (poor contact on the fold)
What it feels like
Often you can feel:
- A raised ridge or folded-in crease
- A more pronounced physical deformation than simple waviness
Where it shows up most
- Across many consecutive pages (because the gusset persists in the web)
- In consistent locations on the page
- Sometimes nearer one side/edge if the tuck originates at the web edge
Simple at-home checks
Check A: Repeatability test
Flip through multiple pages:
- If the same crease appears in the same place again and again, gussets/web issues are likely
Check B: Feel for a “tucked” ridge
A gusset often feels like a sharper folded ridge, not just a soft wave.
Check C: Look for print distortion along the crease
If text or images are distorted precisely where the crease runs, it supports a web-formed crease defect.
Common look-alikes (and how to separate them)
1) Web wrinkling
Web wrinkling is a broader category of wrinkles/creases formed on press. Gussetsnare a specific type of web wrinkle: A tucked fold/crease
2) Handling creases (shipping/reader damage)
Handling creases usually:
- Don’t repeat consistently across many pages
- Are more random and localized
Gussets often:
- Repeat across many pages in a consistent position
3) Impression marking
Impression marking is a pressure imprint (dent) matching printed shapes.
Gussets are actual creases/wrinkles, usually independent of the image shape.
4) Chill roll marking / banding
Chill roll marking creates repeating gloss bands, not a physical crease ridge you can feel.
Gussets are physical creases with distortion.
5) Wrinkling from moisture after printing
Moisture waviness (cockling) is broad waviness without a sharp crease line and doesn’t usually repeat in a crisp, consistent crease location.
Impact on book quality and readability
Readability
Gussets can:
- Distort text along the crease
- Break strokes in letters
- Create glare or shadow lines where the crease catches light
Appearance
- Pages look defective or damaged
- Photos and graphics can be visibly warped
- Repeated defects across many pages reduce perceived quality significantly
Finishing side effects
Severe creases can also affect folding/trimming consistency and feel “bumpy” in the book block.
Industry standards and “acceptable tolerances”
Gussets are typically considered unacceptable when visible because they are physical paper deformations that distort print.
Usually acceptable
- Extremely minor waviness that doesn’t distort printing (not typical of true gussets)
Usually not acceptable
- Visible crease lines that repeat across pages
- Distortion through text/images
- Sharp folded ridges you can feel
- Defects in prominent image sections or the cover
A useful rule of thumb: If you can see and feel a crease line and it repeats across multiple pages, it’s almost certainly a production defect worth replacing.
What you can do as a buyer
- Gussets are a production/web-handling defect; a replacement copy typically won’t have the same issue unless it affected a large portion of the run
- Photograph
- A close-up showing the crease and print distortion
- A wider shot showing the crease repeats in the same location on multiple pages
Helpful wording for support: "The book has gussets/web crease defects—repeating tucked wrinkles that distort print along a crease line across multiple pages.."