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Conversion profiles

Conversion profiles define how the Pdftools SDK converts an input file and renders it in an output file. A profile contains a set of conversion parameters that combine to support a practical use case. For example, creating documents for viewing, archiving, or fax transmission.

Although a conversion profile provides default parameters for a specific use case, you can adjust most parameters to suit the requirements of a document workflow.

The Pdftools SDK provides two types of conversion profile:

PDF to image conversion profiles​

PDF to image conversion profiles provide default parameters for converting PDF documents to images. The Pdftools SDK provides three image conversion profiles:

Viewing​

Use the Viewing profile to convert PDFs to rasterized JPEG or PNG images for web and desktop viewing applications or thumbnails.

For JPEG and PNG images, the default output uses the RGB color space, has a resolution of 150 DPI, and renders on a white background. For PNG images, the profile applies a lossless compression algorithm. For JPEG images, the profile applies JPEG compression with a default quality factor of 85.

You can also set the following options:

  • Quality factor (JPEG): 0 - 100
  • Color space (JPEG): RGB, CMYK or gray
  • Color space (PNG): RGB or gray
  • Background: Transparent or white
  • Resolution: DPI (0.0 - 10,000.0) or as a maximum image size (in pixels)

Archive​

Use the Archive profile to convert PDF documents to TIFF images for archiving as rasterized images.

By default, the output image inherits the color space of the PDF document, has a resolution of 300 DPI, and uses the LZW compression algorithm.

You can also set the following options:

  • Compression algorithm: LZW, JPEG or flate
  • Color space: inherit the color space of the PDF document, RGB, CMYK or gray
  • Resolution: 0.0 - 10,000.0 DPI

Fax​

The Fax profile converts PDFs into TIFF-F conforming rasterized images for fax transmission. The output format is a multi-page TIFF file, which contains all PDF pages converted into rasterized images.

By default, the profile scales output images to a width of 1728 pixels, with a horizontal resolution of 204 DPI and a vertical resolution of 98 DPI. Dithering converts all colors and grayscale tones to bitonal. The profile compresses the output image using the CCITT Group 3 compression algorithm.

You can use the following options:

  • Compression algorithm: CCITT Group 3 or CCITT Group 4
  • Vertical resolution: 98 DPI (Standard) or 196 DPI (High)
  • Dithering mode: Algorithm used when converting color or grayscale pixels to bitonal:
    • Halftone: Ordered (clustered-dot) halftoning. The default; produces a repeating pattern that is well suited to fax transmission and laser reproduction.
    • None: No dithering. A fixed threshold maps pixels to black or white. Produces the smallest files and the sharpest edges, but loses tonal information.
    • FloydSteinberg: Floyd‑Steinberg error-diffusion dithering. General-purpose tonal reproduction.
    • Atkinson: Atkinson error-diffusion dithering. Preserves local contrast in photographs better than Floyd‑Steinberg at the cost of some shadow detail.

Image to PDF conversion profiles​

Image to PDF conversion profiles provide default parameters for converting images to PDF files. The Pdftools SDK provides two image conversion profiles:

Default​

Use the Default profile for document workflows that need to convert images to PDF documents but don’t have long-term archiving or accessibility requirements.

By default, the profile places images on A4-sized (210 mm x 297 mm) pages in portrait orientation with 20 mm (0.79 in) margins. The Default profile scales large images down to fit the page. The default PDF conformance level is PDF 1.7.

You can also set the following options:

  • Scaling options: Import all images in portrait orientation, automatically detect scaling based on image dimensions, or automatically detect scaling based on image type
  • Page dimensions: standard (A3, A4, A5, Letter, Legal) or custom page sizes, in portrait or landscape orientation
  • Page margins: Standard or custom page margins
  • PDF conformance: PDF 1.x or PDF 2.0

Archive​

The Archive profile is designed for document workflows that need to convert images to PDF files and comply with long-term archiving or document accessibility requirements.

By default, the output of the Archive profile matches the output of the Default profile, except that the default PDF conformance level for the Archive profile is PDF/A-2b.

The same options apply to the Archive profile as to the Default profile. However, the following additional options are available:

  • PDF conformance: PDF/A-1b, PDF/A-1a, PDF/A-2b, PDF/A-2u, PDF/A-2a, PDF/A-3b, PDF/A-3u, or PDF/A-3a
  • Accessible content: Provide language and alternate text for each imported image (required for level A conformance)
tip

For PDF/A-1a, PDF/A-2a, and PDF/A-3a conformance, you must provide accessible content. For more information about creating accessible PDF documents, see Convert image to Accessible PDF.