Guidelines for Uploading PDF Files

Created: 2026-07-15

This document describes the recommended specifications for PDF files uploaded to the Webarch system. Following these guidelines ensures optimal rendering, text extraction, archiving compatibility, and the best possible reading experience.

1. Recommended PDF Standard

We strongly recommend exporting files using one of the following formats.

Preferred formats

• PDF/A-2B

• PDF/A-2U

These formats ensure that all required resources are embedded in the document and that the file remains compatible for long-term archiving and processing.

Alternative supported formats

• PDF/A-1B

• PDF/X-3

Recommendation: Whenever possible, use PDF/A-2B or PDF/A-2U.

2. PDF Version

Recommended PDF version:

• PDF 1.7

This version provides full compatibility with modern PDF processing engines and ensures correct handling of:

• Transparency

• Fonts

• Metadata

3. Archival Format (PDF/A)

Files should preferably be exported using a PDF/A archival format.

Benefits of PDF/A

• All fonts are embedded

• Color profiles are included

• No external dependencies

• Consistent rendering across systems

• Long-term preservation

Using PDF/A significantly improves the stability of Webarch's text extraction and page rendering.

4. Font Requirements

All fonts must be embedded in the PDF.

Additionally:

• Fonts should contain proper Unicode mappings.

• Avoid subset fonts with incorrect character encoding.

• Incorrect font mappings may prevent proper text extraction.

• If fonts are incorrectly mapped, OCR may be required to extract text.

5. Compression and Optimization

Avoid uploading heavily optimized or pre-compressed PDFs.

Over-optimized PDFs can introduce rendering problems and reduce processing quality.

Common issues caused by excessive compression

• Visible lines between images or page elements

• Rendering artifacts in gradients or transparent objects

• Reduced image quality

• Broken layers or flattened content

For example, browsers such as Google Chrome may display visible lines around images when rendering heavily compressed PDFs.

Recommendation: Do not optimize the PDF for web delivery before uploading it to Webarch.

6. Image Quality

Recommended settings:

• Use print-quality images whenever possible.

• Avoid unnecessary downscaling.

• Avoid aggressive image compression.

• Print-ready PDFs are generally ideal for Webarch.

In most cases, the same PDF used for professional printing is also suitable for Webarch ingestion.

7. Best Practices

For the most reliable processing:

• Export directly from the original layout software (e.g. Adobe InDesign).

• Use a standard PDF/A export profile.

• Avoid manual post-processing or third-party PDF optimization tools.

• Ensure fonts and ICC color profiles are embedded.

• Validate the PDF using a PDF/A validator when available.

8. Recommended Settings Summary

Recommended Workflow

1. Create the PDF directly from the original layout application.

2. Export using PDF/A-2B or PDF/A-2U.

3. Verify that fonts are embedded.

4. Avoid additional optimization or compression.

5. Upload the original print-quality PDF to Webarch.