Below you will find recommendations for optimising the file size and speed when performing the PDF export:
General
- The export to PDF format may cause different file sizes even when using the identical database but on different operating systems and / or different printer drivers.
- If dashed or dotted lines / frames are used in the project file, the resulting PDF file can become very large, since each dot / dash is represented as a single PDF record. In order to keep the resulting file size small, solid lines / frames should be used for the PDF export.
From List & Label 28: Enable the option LL_OPTION_USESIMPLEWINDOWSPENSTYLE_FRAMEDRAWING to have simple default border lines for tables and objects such as dotted, dashed, dashed-dotted, and dashed-dotted-dotted more effectively output directly by Windows or the PDF viewer. This can lead to higher overall performance and also smaller PDF export files.
From List & Label 29: Use the PDF export option PDF.UseSimpleFrames instead of the global option LL_OPTION_USESIMPLEWINDOWSPENSTYLE_FRAMEDRAWING. - List & Label is able to create PDF/A-compliant documents of type PDF/A-1a. However, an essential feature of this type is that fonts and images are embedded in the document. In addition, other metadata and color information is collected, which may affect the file size in the sum.
- If encryption is enabled, the generation of the PDF document may be delayed. Note: Up to version 25 the PDF.Encryption.Level option could be used to specifically control the type of encryption. As of version 26, encryption is controlled implicitly with the help of PDF.Conformance and activated with PDF.Encryption.EncryptFile.
- Only up to version 25: The PDF.CompressStreamMethod option determines how dense the PDF document should be compressed. Depending on the content you can achieve an even smaller file by changing the compression method.
Dealing with fonts
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With the option PDF.ExcludedFonts fonts can be explicitly excluded from embedding in the PDF, which can reduce the resulting file size. The Windows Fontmapper will be used for displaying excluded fonts. The font “Arial” is not embedded by default, because it can be replaced by identical PostScript fonts.
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From version 26: When using symbols/(special) characters that are to be displayed within a font (not images or graphics!), make sure that the selected font can also display the desired symbol/(special) character itself. If this is not the case, the execution time during PDF creation may be delayed because a suitable font must first be found in the system that can also display the desired character in the PDF context. In addition, the PDF file size may increase, as the font found must also be integrated.
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Note: The following options regarding the handling of fonts are only valid up to and including version 25. As of version 26, a completely renewed PDF export is available which contains optimized automation for the handling of fonts and thus no longer supports the options listed below for fonts:
- In general, if no fonts are embedded (see option PDF.FontMode = 0) the file size is smaller. For displaying the fonts the Windows Fontmapper will be used.
- Unicode / multibyte characters can be embedded with the help of the property PDF.FontMode as Type3 embedded fonts (value: 8) or CID embedded fonts (value: 6) (Character Identifier). When using CID, the file size may increase whereas in Type3 the file size usually can be kept small.
- If you experience that the spacing and / or positioning for various fonts in PDF are not correct, you can use the PDF.ExactPositioning option and set it to “1”. This causes that each letter is positioned seperately. However, as a result, the PDF file will be larger.
- For the authentic representation of OpenType variable fonts, the font embedding “Use Type 3 fonts” should be used (see option PDF.FontMode = 8).
Use of images
- JPEG or PNG files used as images in the project file will be exported without being converted by List & Label. This means that depending on the size of the image the file size also directly affects the resulting PDF. All other image formats are always converted to JPEG. This may decrease the quality of the image through the conversion process. Identical images are not embedded multiple times to keep the file size small.
- With the option PDF.JPEGQuality you can adjust the quality and the file size for any JPEG conversion. This option will only affect images that are not already saved as a JPEG file.
- You can force the conversion for images and objects to JPEG with the designer object properties “Save as JPEG” (for images) and “Export as Picture” (for various objects).