Which PDF Standard Is Better to Choose

For some tasks, certain PDF standards will fit better or vice versa worse. In this article, we will try to determine which PDF standards for which cases it makes sense to choose.

PDF 1.7 vs PDF 2.0

At the moment there is no big difference between Aspose.Words' PDF 1.7 and PDF 2.0 output.

Aspose.Words PDF 2.0 output just allows to use some new features, such as a new encryption algorithm. But there may be difficulties in handling of PDF 2.0 output in older PDF viewers. So, PDF 2.0 should be used if new features are needed. Otherwise, PDF 1.7 should be used.

This may be reconsidered later.

When to Use PDF/A and Which Version

PDF/A is a format for archiving and long-term preservation. Generally it is required by authorities, archives, libraries, and so on. So, the use of PDF/A compliance is dictated by the requirements of the PDF consumer. And if PDF consumers do not require it, then it should not be used.

The PDF/A version should be selected to be the highest acceptable for the consume, since higher versions are more reliable for Aspose.Words PDF/A output. However, the conformance level for PDF/A-1, PDF/A-2, PDF/A-3, or PDF/A-4 should also be selected according to consumer requirements. Thus, if level A is required, then it should be used, and if level B/U is required, then both level B/U and level A could be used.

Note that level A documents are accessible but take more space than level B/U documents.

When to Use PDF/UA

PDF/UA should be used if PDF consumers require it. Also it could be used if you just need the accessible PDF output, but it will take more space compared to regular PDF output.

FAQ

  1. Q: What is the practical difference between PDF 1.7 and PDF 2.0 output in Aspose.Words?
    A: PDF 2.0 adds support for newer PDF features such as the PdfEncryptionAlgorithm.Aes256 encryption method. Functionally the documents look the same, but older PDF viewers may not fully support PDF 2.0. Use PDF 2.0 only when you need those new features; otherwise stick with PDF 1.7 for maximum compatibility.

  2. Q: When should I choose a PDF/A version instead of a regular PDF?
    A: Choose PDF/A when the document must be archived for long‑term preservation or when a regulatory body requires it. PDF/A guarantees that all fonts, colors, and resources are embedded, making the file self‑contained. If no archival requirement exists, a regular PDF (PDF 1.7 or 2.0) is usually smaller and faster to generate.

  3. Q: How can I set a specific PDF/A conformance level (e.g., PDF/A‑2b) in Node.js?
    A: Use PdfSaveOptions and set its pdfStandard and compliance properties. Example:

    const aw = require("aspose.words");
const doc = new aw.Document("input.docx");

const saveOptions = new aw.saving.PdfSaveOptions();
saveOptions.pdfStandard = aw.saving.PdfStandard.PdfA2;
saveOptions.compliance = aw.saving.PdfCompliance.PdfA2b; // or PdfA2a / PdfA2u

doc.save("output.pdf", saveOptions);

    This generates a PDF/A‑2b compliant file.

  4. Q: What is PDF/UA and when is it required?
    A: PDF/UA (Universal Accessibility) is a PDF standard that ensures the document is accessible to people with disabilities, complying with WCAG 2.0 and Section 508. Use PDF/UA when your audience includes users who rely on assistive technologies or when accessibility is a legal requirement.

  5. Q: Does using PDF 2.0 increase the file size or cause compatibility problems?
    A: PDF 2.0 itself does not significantly increase file size; the size impact comes from the optional features you enable (e.g., advanced encryption, embedded color profiles). The main risk is compatibility: some older PDF readers may not fully support PDF 2.0 features, which can lead to rendering issues. Test the generated PDF with the target viewers if you decide to use PDF 2.0.

Conversion to PDF/A and PDF/UA Working with PDF/A or PDF/UA