LensPDF LensPDF
lensPDF

CMYK + spot separations · TAC heatmap · Densitometer · Layer toggles · Annotation

See every ink,
every plate.

Embeddable web PDF viewer purpose-built for prepress review. Inks, plates, dielines, varnish — every layer the press operator needs, inspectable in any browser.

Try it now View on GitHub Read the docs

The viewer prepress actually deserves

LensPDF surfaces ink separations, TAC, layers, and annotation overlays — the things a prepress operator actually needs when looking at a job. Embeddable, AGPL-3.0-licensed, no vendor lock-in.

Per-Channel Separations

Toggle process (CMYK) and spot channels per page. Isolate single inks, inspect overprint behavior, verify plate counts — all in the browser.

TAC Heatmap

Total-area-coverage overlay flags ink-limit violations per pixel. Click any spot to read the densitometer across every separation.

Densitometer Probe

Single-pixel color probe across every channel. Read CMYK, spot, and TAC at any point — with over-limit warnings when a region exceeds your ink coverage.

Layer Toggles

PDF optional-content groups render as toggleable layers. Dieline, white ink, varnish, and braille each get their own visibility switch — no server round-trip per click.

Pin-Sharp Viewing

Smooth zoom from 25% to 400% on desktop, pinch-zoom on touch, page thumbnails with at-a-glance issue counts. Works equally well on a 32-inch monitor and a phone.

Measurement Toolkit

Ruler that reads in mm, inches, points, picas, and agate at once. Trim, bleed, and crop boxes overlaid on the page with sizes you can read without doing math.

Annotation Toolkit

Pen, arrow, rectangle, ellipse, text, and highlight tools. Per-page autosave, sidebar thread of every comment across every page, read-only share links for clients.

Plugin Slots

Custom toolbars, panels, hotkeys, dialogs, and overlay layers. Drop-in shadow replacements let third-party panels override built-ins with no fork.

Brand & Theme

Theme tokens for every surface, light and dark out of the box, mobile-first chrome, accessibility and keyboard navigation throughout. Your logo, your colors, your domain.

Embeddable

Drop the viewer into any React, Astro, Next.js, or vanilla host. Tools you haven't wired simply don't appear — no clutter, no dead buttons.

Annotation Overlays

Render any preflight findings — engine, PitStop, callas, Acrobat — directly on the page. Filter by severity, jump to location, hover for context.

Edge-Cached

Stateless reference backend, immutable page tiles tagged for one-click Cloudflare cache purges. No telemetry, no phone-home — bring your own analytics.

See the full feature breakdown

Open source · managed hosting

Independent tools. Pick the ones you need.

A toolkit of focused, standalone PDF utilities — extraction, preflight, viewing, assembly, imposition planning, and an asset store. Each one plugs into the prepress workflow you already run. Use the open source yourself, or let us host any single tool for you on work.withsynergy.io.

compile-pdf

Beta · OSS Cloud

Programmatic PDF assembly — a deterministic API build step for rewriting and generating print-ready PDFs.

Visit site GitHub Cloud hosted

artwork-pdf

Beta · OSS Cloud

WYSIWYG canvas editor for label and packaging artwork — PDF/X-4 output, flexo support, and a full create-to-RIP workflow.

Visit site GitHub Cloud hosted