Building one PDF from many different sources

A tender response, a case bundle, a grant application, a portfolio: documents assembled from parts produced by different people in different software. The assembly is where they go wrong.

Convert everything to PDF first

Do not try to combine mixed formats directly. Convert each source into a PDF on its own, check it, and only then merge. Debugging one bad conversion inside a ninety-page bundle is far harder than catching it on its own.

• Word to PDF for documents. Check the output rather than assuming: complex layouts, unusual fonts and embedded objects are where fidelity is lost.
• Excel to PDF for spreadsheets. This is the riskiest conversion in the list — a sheet that is wider than a page will break somewhere, and the tool chooses where unless you set a print area first.
• JPG to PDF or PNG to PDF for photographs and screenshots. See images to PDF for orientation and sizing.
• HTML to PDF for web content.
• Existing PDFs need nothing.

Standardise before merging

Merging copies each page exactly as it is, which is why quality is preserved — and also why inconsistency is preserved.

Page size. A4 (210×297 mm) and US Letter (216×279 mm) look nearly identical on screen and produce visibly ragged output when printed or scrolled. Pick one and make every source match it before conversion.

Orientation. Landscape spreadsheets among portrait text pages are sometimes correct and sometimes an accident. If deliberate, keep them consistent — all landscape pages rotated the same way, so the reader turns the page once in one direction.

Margins. Sources with wildly different margins read as a stitched-together document, because that is what it is. Where you control the source, align them.

Merge and order

Merge PDF combines the files in the order you arrange them. Two things reliably catch people out:

Filenames sort as text, so section10 comes before section2. Zero-pad numbers — section02, section10 — and the problem disappears everywhere, not just here.

And the merge order is the order shown, not the order you selected the files in. Check the list before running it. Details in merging PDF files correctly.

If the order needs adjusting afterwards, Organize PDF reorders, rotates and deletes pages in the combined file.

Finish the document

Once assembled, a few steps turn a stack of pages into something that reads as one document.

Page numbers. Apply them to the merged file with Page Numbers so numbering is continuous. Numbers carried over from individual sources will each restart at 1 and contradict each other — remove or cover those where possible.

A contents page. For anything over about twenty pages, a contents page with final page numbers is the difference between a bundle someone can navigate and one they scroll through. Make it last, once the pagination is fixed.

A cover. A single page with the title, date and author makes the file identifiable when it is one of thirty in a reviewer's folder.

Metadata. Set a real title in PDF Info. It is what appears in the browser tab and in search results within document systems, and by default it is often the filename of whichever source happened to be first.

Check the whole thing at the end

Page through the assembled document from start to finish. You are looking for pages that came in rotated, sections in the wrong order, duplicated pages from an overlapping source, and orphaned headings at page breaks.

Then run the pre-send checks — an assembled document contains the metadata and hidden content of everything that went into it, from every contributor.