PDFGym
EN

Preflight a PDF for print

or drop one here

Print settings

Start with the workflow closest to the job. The report records every value.

300 DPI · 3 mm bleed · managed color
Choose a PDF first.

A press rejects files for boring reasons: a web logo at 72 DPI, three millimetres of missing bleed, one RGB photo in a CMYK job. This page checks the structure of your PDF against the workflow you name, keeps the page or object behind every finding, and never touches the file. Anything that needs a certified press-proof renderer stays honestly marked as not checked.

The brochure the offset press sent back

A preflight run earns its keep the week a deadline is real. Run it before the file leaves your hands, not after the press calls.

A studio manager is sending brochure-spring-12pp.pdf, 12 pages, to an offset house for 2,000 copies. Last quarter the same press bounced a job for a 72 DPI web logo and zero bleed on a trimmed cover. This time she opens the file here, leaves the Commercial workflow selected, and presses Run print preflight.

The report flags four placed images under the 300 DPI floor and a missing bleed box on the cover, each with its page number attached. She swaps the logo for the 300 DPI master, extends the cover background 3 mm past the trim in the layout program, exports again, and the second run comes back clean. The round trip she avoided would have cost two days.

Five passes from file to verdict

  1. Open the PDF

    Press Choose a PDF, or drop the file on the page. The Print settings panel underneath describes the workflow the report will judge against.

  2. Name the workflow

    Pick Commercial, Digital, or Large format, then tune Minimum image DPI, Required bleed in millimetres, and Color policy if the press gave you its own numbers. The preset note always shows the active combination, and the report records every value used.

  3. Run the static checks

    Press Run print preflight. Every page opens independently in pdf.js and pdf-lib, boxes and bleed get measured, fonts and images get traced, and every finding cites the page or object behind it.

  4. Simulate the press output

    For ink questions, press Run press simulation. The local Poppler renderer loads only for this check and draws separation plates, process ink coverage against your limit, and overprint previews off and on. Keep the tab open while it works; Stop press simulation cancels it.

  5. Save the evidence

    Narrow the list with the All, Failed, Warnings, Not checked, and Passed filters, then press Download report for the human-readable file or Download JSON evidence for the versioned archive. Both carry the source file name, such as brochure-spring-12pp-print-preflight.html.

Reading the inventory and the evidence

Start at the top. The Document inventory counts pages, fonts, placed images, and output intents, flags how many images sit below your floor, and quotes any PDF/X claim as inspected, never certified. The verdict line above it counts the items that need a decision before production, and the proof line records that every page opened in both readers with the source hash noted.

Each finding then carries its own evidence: the page with the short bleed box, the image with its effective DPI, the font that never got embedded, the script action a press RIP would choke on. Findings sort into Failed, Warnings, Passed, and Not checked, and that last group matters most. Unknown is kept separate from passed, so a quiet report never pretends a check ran when it did not.

The three print workflows and their starting values
WorkflowImage floorBleedOutput intent
Commercial300 DPI3 mmRequired
Digital200 DPI0 mmRecommended
Large format150 DPI3 mmRecommended

The press simulation brings its own two settings. Ink coverage limit opens at 300 percent, the ordinary ceiling for coated offset work; when the job ticket names another number, type that instead. After the run, four metrics summarize the plates: Maximum ink against your limit, Color channels with the named spot count, Overprint changes with affected pages, and Peak Wasm heap with the tile count. The side-by-side overprint previews show what the numbers mean on the actual pages.

What the static pass cannot see

Structure inspection finds missing boxes, soft placements, stray color, unembedded fonts, transparency, overprint notes, and active content such as JavaScript. It cannot render ink on paper. That is the job of the optional press simulation, which draws process and named spot plates in bounded tiles, measures maximum ink against your coverage limit, and shows overprint previews off and on side by side.

Even that pass has an edge: it remains a simulation at proof resolution rather than a certified PDF/X validation, and the ICC production soft proof stays not checked. For a contract proof or a certified conformance stamp, the file still needs an accredited validator and a calibrated proof from the press.

Mistakes that waste a preflight run

The classic one is judging a banner by offset rules. A poster viewed from three metres is fine at 150 DPI, so running it against the Commercial floor rains warnings that mean nothing. Match the workflow to the job first: commercial for offset, digital for short runs and office devices, large format for banners and posters.

The second is confusing stored pixels with effective DPI. A 300 DPI photo stretched to twice its size prints at 150 effective, and that is the number the check flags. When the same picture fails everywhere, Extract images shows its true stored size, and Size breakdown shows whether oversized originals are also bloating the file. And never squeeze a print file through Compress PDF just to fit an email outbox; downsampling wins the attachment and loses the job. Send a link instead.

When a human prepress operator still wins

This report checks structure, not taste or intent. It cannot tell whether the spot color named Brand Red is the right ink, whether the trapping suits the stock, or whether page 7 was supposed to print upside down for the fold. When the press quotes a job with special stock, varnish, or die cuts, send the PDF and this report together and let their prepress desk have the last word. Before the file travels anywhere, Privacy scan wipes author and editor traces from its metadata.

Short answers about print-ready PDFs

My press asked for 3 mm bleed and 300 DPI. Where do I set that?
That is exactly the Commercial starting point. Open the file, confirm the preset note reads 300 DPI with 3 mm bleed, and press Run print preflight. When the press quotes different numbers, type them into Minimum image DPI and Required bleed first.
Why did my RGB photos pass on one run and warn on the next?
The Color policy changed between runs. CMYK and spots only flags any RGB content, while Managed RGB, CMYK and spots accepts it only when the file embeds an output profile. Pick the policy your workflow actually prints.
What does Not checked mean next to ICC soft proof?
It means the check honestly did not run. The press simulation renders plates, ink coverage, and overprint previews locally, but a calibrated ICC production proof needs the press hardware, so that row stays unknown rather than pretending.
Can I archive the report with the job ticket?
Yes. Download report saves a readable HTML file and Download JSON evidence saves a versioned JSON archive, both named after the source file. Either one staples cleanly to a job folder.
Does the press simulation send pages to a server for rendering?
No. The Poppler renderer loads into the page and draws its tiles on your device. Closing or reloading the tab stops it, which is why the tool warns you to keep the tab open.
What ink coverage limit should I type?
Start with the 300 default for ordinary coated offset work. When the press or the paper profile names its own ceiling, type that number instead; the Maximum ink metric then judges the plates against your value.

More tools that inspect before they change

Each tool below runs the same local way: your file stays on your device, every run ends in a named download or a plain report, and no account gets in the way.

Fix what the report found