Step-by-step guide
Bifrosta
Turn text-PDF page references into reviewed internal links. Find literal page references in a text PDF, review the destinations, and export a separate PDF with clickable internal links.
You have a manual, handbook or report saved as a text PDF, its cross-references (“see page 12”) are plain text, and you want readers to be able to click them.
The guide and practice files are free to read and download. The complete program is in the paid download; the free practice pack does not include it.
See it in use
Link page references in a six-page booklet
A screenshot walkthrough with fictional practice data. Select a step to explore.
1. Start with
Link page references in a six-page booklet
The fictional balcony herb PDF contains seven “see page” references.
Sample files and contents
examples/bifrosta/balcony-herb-handbook.pdf: a fictional 6-page text PDF, numbered 1–6 in the footer, with seven “see page N” references. One of them points to page 9, which does not exist.
Practice files and guides are free. The complete app is included only where the product page says so.
2. In the app
Try it in three steps
- Load the PDF and find candidate page references.
- Apply the zero-offset calibration and approve six valid candidates.
- Save the linked PDF and inspect its first page.
Show every click and setting
- Open your local Bifrosta page, click Choose a PDF… and select balcony-herb-handbook.pdf.
- Keep the default reference text “see page ” and click Find candidates.
- The calibration step suggests offset 0 (6 of 6 page numbers agree). Click Apply, then Review 7 candidates.
- Click Approve 6 unambiguous, then Continue to export (6 links ready).
- Click Save balcony-herb-handbook.bifrosta.pdf, and optionally Save review job (balcony-herb-handbook.bifrosta.json).
3. The result
Inspect the result
The six-page PDF has six clickable internal links. Its out-of-range page-9 reference stays blocked.
What to check in the practice result
Bifrosta reports “7 candidate reference(s) found”, with 1 blocked: “see page 9” is out of range. Your browser downloads balcony-herb-handbook.bifrosta.pdf, which has the same 6 pages and 6 clickable links. For example, “see page 4” on page 1 opens page 4. The status line shows “6 link annotation(s) written”.
The screen and downloaded PDF come from the same six-page fictional herb booklet. Six links were exported; the invalid page-9 reference was excluded.
See the workflow at a glance
Choose a short explanation, then follow the worked example below. Check the requirements and compatibility before using your own files.
Make “see page 4” take the reader there.
Your booklet already tells readers where to look. Bifrosta turns literal page references in a text PDF into internal links after you review their destinations. The six-page balcony herb example finds seven references, blocks the impossible page 9 and exports six clickable links in a separate PDF. Open the local app in desktop Chrome and keep the source unchanged. There is no OCR, and encrypted or signed PDFs are unsupported; use one reference form per run.
View the illustrated card
Before you start
- Desktop Google Chrome or another Chromium-based browser. The tool was checked in desktop Chrome; other browsers are not verified.
- A text-based PDF (you can select its words in a PDF reader). Scanned pages without text, encrypted, damaged and digitally signed PDFs are refused.
- References written in one consistent form with ordinary digits, for example “see page 35”.
- Open app/index.html in desktop Google Chrome.
Your first result
Open the downloaded local edition
Buy and extract the Bifrosta ZIP, then open its Bifrosta folder. Open app/index.html in desktop Google Chrome. Follow the illustrated example below before buying; the program runs from your purchased local copy.
Open Bifrosta
In your open local copy, follow the controls described below. The five steps across the top are Document, Pattern, Calibration, Review and Export.
Choose your PDF
Under “1. Open a text PDF”, click Choose a PDF… or drop the file on the page. Bifrosta shows the page count and “text layer found”. The file is read in your browser and is never modified.
Describe the reference
Under “2. Describe the reference”, type the words before the number in Text before the number (default “see page ”) and any text after it. To check the wording, use Find wording in this PDF. Results show eight matching sheets at a time; use Later matches to reach further sheets, or Go to sheet for a known sheet number. Select a match to inspect its page preview, then click Find candidates.
Match printed numbers to PDF pages
Under “3. Calibrate printed numbers”, Bifrosta suggests an offset between the printed page numbers and the pages of the file. If the suggestion is right, click Apply. Otherwise, under SET IT FROM ONE KNOWN PAGE, enter a printed number and the PDF page (sheet) it is on, then click the Use offset button. Books with a cover or front matter usually need an offset; confirm it on the page preview. Then click Review N candidates.
Review every reference
Under “4. Review every candidate”, each reference shows where it was found and the page it will open. Click Approve or Reject for each one, or Approve N unambiguous to approve all references with a valid target. References that point outside the document are blocked. Click Continue to export (N links ready).
Save the linked copy
Under “5. Save a linked copy”, optionally tick Draw a thin blue border around each link, then click Save <name>.bifrosta.pdf. Your browser downloads a new PDF. Click Save review job (<name>.bifrosta.json) if you want to resume or re-check the review later.
Check the result
Open the saved copy in your PDF reader and click a few links to confirm each one opens the expected page.
A worked example
Link the cross-references in a six-page herb booklet
Input: examples/bifrosta/balcony-herb-handbook.pdf: a fictional 6-page text PDF, numbered 1–6 in the footer, with seven “see page N” references. One of them points to page 9, which does not exist.
- Open your local Bifrosta page, click Choose a PDF… and select balcony-herb-handbook.pdf.
- Keep the default reference text “see page ” and click Find candidates.
- The calibration step suggests offset 0 (6 of 6 page numbers agree). Click Apply, then Review 7 candidates.
- Click Approve 6 unambiguous, then Continue to export (6 links ready).
- Click Save balcony-herb-handbook.bifrosta.pdf, and optionally Save review job (balcony-herb-handbook.bifrosta.json).
Expected result: Bifrosta reports “7 candidate reference(s) found”, with 1 blocked: “see page 9” is out of range. Your browser downloads balcony-herb-handbook.bifrosta.pdf, which has the same 6 pages and 6 clickable links. For example, “see page 4” on page 1 opens page 4. The status line shows “6 link annotation(s) written”.
Troubleshooting
The PDF is refused.
Bifrosta only accepts text PDFs. Scanned pages without a text layer and encrypted, damaged or digitally signed files are refused, and the reason is shown. Export the document again as a text PDF from the program that created it.
No candidates are found.
Copy the exact wording from the document preview in the Pattern step into Text before the number. Keep Ignore letter case and Tolerate different spacing and line breaks ticked.
Links open the wrong page.
The offset is wrong. Go back to Calibration, enter a printed number and the PDF page it appears on under SET IT FROM ONE KNOWN PAGE, then review again.
I closed the tab and lost my decisions.
Bifrosta stores nothing in the browser. Save a review job before closing, then use Load review job… in the Pattern step with the same PDF to resume.
Where is the sample PDF?
The purchased local edition contains samples/book-with-refs.pdf. The free guide pack contains the separate six-page practice PDF at examples/bifrosta/balcony-herb-handbook.pdf.
Compatibility & limits
- Text PDFs only; there is no OCR.
- Ordinary (Arabic) page numbers only; Roman numerals and complex page labels are not supported.
- One reference form per run, such as “see page”; run again for another form.
- Digitally signed PDFs are refused, because adding links would invalidate the signature.
- Nothing is kept in the browser: closing the tab discards the review unless you saved a review job.
- The complete program is supplied as a purchased local download. The public guide and practice data help you assess the workflow before buying.
- Local browser checks used synthetic PDFs in Google Chrome on Linux. A varied real-document corpus, other host environments, and assistive-technology acceptance remain unverified.
Need a hand?
Tell us the product, host application and version, what you tried, and the exact error. Contact support with a fictional example; keep private customer files and passwords out of your message.