Trim, binding, and cover

The default is a 6×9 paperback, perfect-bound — the sealed house design. A book that sets none of the keys below builds exactly that, unchanged. Every other combination is opt-in.

The four choices

Each is a print.* key you set with press config:

press config set print.profile novella-5x8 && \
press config set print.provider lulu && \
press config set print.binding casewrap && \
press config set print.material casewrap

An unsupported combination — a trim a vendor does not cut, a dust jacket at a vendor that offers none, a colour interior at a vendor that prints none — is refused by press check, before any render, naming what went wrong. (The page-count bounds are checked at build time, where the real page count is known.) The trims and inks each vendor supports are captured as data in its provider spec, so the gate is one reviewed matrix, not scattered rules.

Trim comes from a design profile

The trim is not a hand-entered number: it comes from the design profile named by print.profile, because a profile is a sealed, verified geometry — the trim can never disagree with the interior it was laid out for. The house profile is 6×9; other profiles carry their own trim and margins.

press config set print.profile novella-5x8   # a 5x8 novella

Selecting a profile changes the page for both the reading PDF and the print interior. Adding a new trim is adding a profile, not editing the pipeline.

The shipped profiles

Each carries its own margins, figure cap, structural typography, and web reading measure — the design, sealed by its major. The large-print profile keeps the house structure but sets a larger base face and markedly more open leading, the single change that most helps a low-vision reader; the digest profile sits between the novella and the house; the mass-market profile is the densest, with the tightest leading and narrowest measure so a long novel fits a pocketable spine.

A trim is only usable at a vendor that cuts it, so the design and the provider must agree. Every vendor cuts 7×10 and 5.5×8.5, but the 4.25×6.87 pocketbook is a Lulu trim only — selecting mass-market-4.25x6.87 with kdp or ingramspark is refused before rendering, naming the trim they do not offer.

A profile carries more than trim. It also seals the interior’s structural typography — the paragraph indent and leading — and the web reading measure — the maximum line length, base font size, and line height of the reader site. These are the design: house-6x9 uses the values the press has always used, and novella-5x8 sets a tighter measure and more open leading to suit the narrower digest page. What a profile does not touch is your book’s identity — the font family and the colour palette — which stay with the aesthetic and override the profile. So choosing a profile changes the design’s proportions; choosing an aesthetic changes its voice.

Colour interiors

The interior prints in a single black ink by default — the cheapest, sealed house discipline, and the honest space for an engraving. A book whose interior wants colour — a cookbook of food photographs, an early reader, a photo-essay — selects a colour design profile:

press config set print.profile house-6x9-color && \
press config set print.provider kdp

house-6x9-color is the 6×9 house geometry, byte-for-byte, with one difference: the interior prints in colour. A text-only page renders identically to house-6x9; the change lifts the print verifier’s single-ink rule and keeps your commissioned plates in colour instead of graying them at intake.

Colour is a profile choice, not an aesthetic one: the aesthetic still cannot tint the interior, so the single-ink craft law is intact — colour is a deliberate, sealed design decision.

It must be paired with a provider that prints colour

Colour stock is a different, heavier paper, so the spine is computed from the provider’s colour caliper, not the white/cream one. Only a provider whose colour stock is documented can be trusted with that number, so a colour interior is refused by press check, before any render, at a provider that does not specify one — the press will not guess a thickness. Today that provider is KDP; Lulu and IngramSpark refuse a colour interior until their colour stock is researched and sourced.

Colour costs more to print, and the page is thicker: KDP offers a standard and a premium colour grade, and print.color-grade picks between them (standard by default).

press config set print.color-grade premium-color   # optional; standard otherwise

When you order a golden copy of a colour edition (see print ordering), the inspection’s colour checklist point is where you confirm the ink reproduces on the physical copy as it does on screen. The Hearthstone Table example is a colour cookbook built this way.

Binding sets the cover’s shape

The binding decides the cover topology, independent of the vendor:

• perfect-bound — a paperback: back · spine · front, flat.
• saddle-stitch / coil — no spine (a flat back · front wrap).
• casewrap — a hardcover printed directly on the board, with a wrap that folds around it (a board turn-in and hinge).
• dust-jacket — a hardcover jacket with flaps.

A hardcover binding needs the provider’s wrap geometry, so it is only available at a provider that offers it (see below).

Material chooses the treatment

• paperback / casewrap — a printed cover.
• linen — a cloth case where the printed field is suppressed: the linen is the finish, and only the dust jacket is printed. (Press never bakes a simulated cloth texture into a real linen cover.)

The provider supplies the numbers

The spine caliper, bleed, safety margin, and hardcover wrap geometry are vendor-specific — the same 6×9 paperback has a different spine width at each printer, because they run different paper and round differently. Select the vendor so the numbers are theirs:

press config set print.provider lulu   # or kdp, ingramspark

What each vendor offers (from their sourced specs):

The full trim × binding × ink matrix and page-count bounds live in each provider’s spec; press check refuses a trim, binding, or ink the vendor does not offer before any render, and press coverwrap enforces it again at the cover geometry.

Which providers exist and what each can actually do is one reviewed ledger, quality/providers.yaml; the copy shipped in the wheel is generated from it, never hand-copied. To add a provider or correct a citation, follow the provider-data update workflow.

Verify and inspect

press verify-print builds and verifies the interior and cover wrap at the selected geometry. The wrap is checked against the same geometry the generator used, so a size regression cannot ship. As always, a physical golden-copy inspection (see print ordering) is what actually qualifies an edition for sale.

A note on versions

Configurable trim, binding, and material change a book’s typography and physical form, so they are a v2 capability — a book opts in by pinning @v2. A @v1 book is 6×9 paperback, unchanged. The design rationale and the sourced vendor numbers are recorded in the print-profiles plan.