Table of Contents

Convert PDF to PDF/A

LM-Kit.NET ships a dedicated archival converter, PdfAConverter, that turns any existing PDF into a self-contained PDF/A document (ISO 19005). Fonts are embedded with reconciled metrics, device colours are calibrated through embedded ICC profiles, prohibited constructs (JavaScript, launch actions, encryption, external references) are removed, prohibited compression is re-encoded, and XMP archival metadata is rebuilt. Text, vector graphics, and layout are preserved. Everything runs 100% on-device and no AI model is required.


Conformance Levels

Level Standard Notes
PdfA1b ISO 19005-1, level B Based on PDF 1.4; prohibits transparency and JPEG2000
PdfA2b ISO 19005-2, level B Based on PDF 1.7; the level most archives request. Default
PdfA3b ISO 19005-3, level B PDF/A-2b plus embedded files of any format

Basic Conversion

using LMKit.Document.Pdf;

var report = PdfAConverter.ConvertToFile("invoice.pdf", "invoice_pdfa.pdf");

Console.WriteLine($"Conforms: {report.Conforms}");
Console.WriteLine($"Fixes applied: {report.FixesApplied}");

Every conversion returns a PdfAConversionReport describing what was detected (FeaturesDetected), what was repaired (FixesApplied), how the output was produced (UsedRasterFallback, RasterTriggers), and whether the result conforms.


Input and Output Modes

The converter accepts file paths, raw bytes, streams, and Attachment objects. Each input mode ships with ConvertToFile, ConvertToStream, and ConvertToBytes variants, all available synchronously and asynchronously:

// File to file
var report = await PdfAConverter.ConvertToFileAsync("in.pdf", "out.pdf");

// Bytes to stream
using var output = File.Create("out.pdf");
var report2 = PdfAConverter.ConvertToStream(pdfBytes, output);

// Anything to bytes, with the report alongside
PdfAConversionResult result = await PdfAConverter.ConvertToBytesAsync("in.pdf");
await File.WriteAllBytesAsync("out.pdf", result.Data);
Console.WriteLine(result.Report.FixesApplied);

Choosing the Fallback Behavior

Some documents carry violations the conforming rewrite cannot repair. The PdfAConversionOptions.Fallback setting decides what happens:

Behavior Effect
Rasterize (default) Rebuild the document from rendered page images with an invisible, searchable text layer. Guarantees a conforming output.
Fail Throw a PdfDocumentException instead of producing a non-conforming file.
ReportOnly Produce the best-effort rewrite and list what remains in Report.UnresolvedViolations. 
using LMKit.Document.Pdf;

var options = new PdfAConversionOptions
{
    Level = PdfAConformanceLevel.PdfA3b,
    Fallback = PdfAConversionOptions.FallbackBehavior.Fail,
};

var report = await PdfAConverter.ConvertToFileAsync("contract.pdf", "contract_pdfa.pdf", options);

When the raster fallback engages, RasterDpi (default 200) and RasterJpegQuality (default 92) control the page image quality, and IncludeInvisibleTextLayer (default true) keeps the output searchable by overlaying the source text invisibly.


Encrypted Sources

PDF/A prohibits encryption, so the converter always produces an unencrypted output. To open an encrypted source, supply the password:

var options = new PdfAConversionOptions { Password = "secret" };
var report = PdfAConverter.ConvertToFile("locked.pdf", "archived.pdf", options);

Console.WriteLine(report.EncryptionRemoved); // True

Batch Archiving Pattern

using LMKit.Document.Pdf;

foreach (string file in Directory.EnumerateFiles(inbox, "*.pdf"))
{
    string target = Path.Combine(archive, Path.GetFileNameWithoutExtension(file) + "_pdfa.pdf");

    try
    {
        var report = await PdfAConverter.ConvertToFileAsync(file, target, cancellationToken: ct);
        log.Info($"{file}: {report.Level}, fixes={report.FixesApplied}, raster={report.UsedRasterFallback}");
    }
    catch (LMKit.Exceptions.PdfDocumentException e)
    {
        log.Warn($"{file}: {e.Message}"); // damaged or password-protected source
    }
}

Reading the Report

Property Meaning
Conforms Whether the output is believed to conform to the targeted level
Level The conformance level that was targeted
PageCount Pages in the produced document
FeaturesDetected Conformance-relevant features found in the source (unembedded fonts, DeviceCMYK, LZW, JPEG2000, transparency, scripts, ...)
FixesApplied Repairs performed by the conversion (fonts embedded, colours calibrated, compression re-encoded, ...)
UsedRasterFallback Whether the output was rebuilt from rendered pages
RasterTriggers The violations that forced the raster fallback, when it was used
EncryptionRemoved Whether the source was encrypted
UnresolvedViolations Violations remaining in the output (only under ReportOnly)

See Also

Share