Conversion profiles
Conversion profiles define how an input file is converted and rendered in an output file. A profile contains a set of conversion parameters that are combined for a practical use case. For example, creating documents for viewing, archiving, or sending via fax.
Although a conversion profile provides default parameters for a specific use case, most of the parameters of a conversion profile can be adjusted to suit the specific requirements of a document workflow.
The Pdftools SDK provides two types of conversion profile:
- PDF to image conversion profiles: used when converting PDF documents to images.
- Image to PDF conversion profiles: used when converting images to PDF documents.
PDF to image conversion profiles
PDF to image conversion profiles provide a set of default parameters that are used when coverting PDF documents to images. The Pdftools SDK provides three image conversion profiles:
Viewing
The Viewing
profile is used to convert PDFs to rasterized JPEG or PNG images for use in web and desktop viewing applications, or for use as thumbnails.
For JPEG and PNG images, the default output uses the RGB color space, has a resolution of 150 DPI, and is rendered on a white background. For PNG images, a lossless compression algorithm is applied. For JPEG images, JPEG compression is applied with a default quality factor of 85.
The following options may also be used:
- 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
The Archive
profile is used 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.
The following options may also be used:
- 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 is designed for converting 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 output images are scaled to a width of 1728 pixels, with a horizontal resolution of 204 DPI, and a vertical resolution of 98 DPI. All colors and grayscale tones are converted to bitonal by applying dithering. The output image is compressed using the CCITT Group 3 compression algorithm.
The following options may also be used:
- Compression algorithm: CCITT Group 3 or CCITT Group 4
- Vertical resolution: 98 DPI (Standard) or 196 DPI (High)
Image to PDF conversion profiles
Image to PDF conversion profiles provide a set of default parameters that are used when coverting images to PDF documents. The Pdftools SDK provides two image conversion profiles:
Default
The Default
profile is used for document workflows that need to convert images to PDF documents, but do not have long-term archiving or accessibility requirements.
By default, the images are placed onto A4-sized (210 mm x 297 mm) pages in portrait orientation with 20 mm (0.79 in) margins. Large images are scaled down to fit the page. The PDF conformance level is set to PDF 1.7.
The following options may also be used:
- 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 documents, 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 set to 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)
For PDF/A-1a, PDF/A-2a, and PDF/A-3a conformance, accessible content must be provided. For more information about creating accessible PDF documents, see Convert image to Accessible PDF.