For each PDF/A-1 validation issue we try to explain what it means and, if possible how to resolve it. For a more technical explanation of the issue we quote the related section of the ISO 19005-1 PDF/A Specification.
6.3.8 is applicable only for files meeting Level A conformance. For Level B conformance the requirements of 6.3.8 can be ignored.
The font dictionary shall include a ToUnicode entry whose value is a CMap stream object that maps character codes to Unicode values [22], as described in PDF Reference 5.9, unless the font meets any of the following three conditions:
- Fonts that use the predefined encodings MacRomanEncoding, MacExpertEncoding or WinAnsiEncoding, or that use the predefined Identity-H or Identity-V CMaps;
- Type 1 fonts whose character names are taken from the Adobe standard Latin character set or the set of named characters in the Symbol font, as defined in PDF Reference Appendix D;
- Type 0 fonts whose descendant CIDFont uses the Adobe-GB1, Adobe-CNS1, Adobe-Japan1 or Adobe-Korea1 character collections.
NOTE Unicode mapping allows the retrieval of semantic properties about every character referenced in the file.