In This Topic ▼

PDF File Comments

The following comments are supported for PDF files:

Value	Meaning
RasterCommentMetadataType.Artist	Person who created the image. Corresponds to the 'Author' key in Document Information dictionary.
RasterCommentMetadataType.Software	Name and version of software package used to create the PDF file.
RasterCommentMetadataType.Title	Title of the image.
RasterCommentMetadataType.Subject	Subject of the document. This will sometimes have entries that are also in Keywords.
RasterCommentMetadataType.Keywords	Keywords, separated by comma (',') or semicolon (';'). Note that the space characters (if present), are part of the keyword.
RasterCommentMetadataType.Creator	The name of the application that created the original file used as a source for the PDF file.
RasterCommentMetadataType.CreationDate	Date and time the file was originally created (YYYY-MM-DDTHH:MM:SS[+/-hh:mm]).
RasterCommentMetadataType.ModificationDate	Date and time of the last file modification (YYYY-MM-DDTHH:MM:SS[+/-hh:mm]).

The PDF comments come from the Document Information Dictionary stored in the Info PDF object. The object is optional and there is only one such object per file. Therefore, all the pages in the PDF file will have the same comments.

RasterCommentMetadataType.CreationDate and RasterCommentMetadataType.ModificationDate have an optional +/-hh:mm suffix indicating the local time zone. The suffix will either be +hh:mm or -hh:mm, depending on whether the local time is ahead or behind UTC. For example:

A document created on January 30, 2022 at 2:33 PM (EST time) would have CreationDate set to 2022-01-30T14:33:00-05:00. That is because EST is 5 hours behind UTC and the daylight savings time is not in effect in January.
A document created in August at the same location should show 2022-08-30T14:33:00-04:00. In August, the suffix would be -04:00 because daylight savings time is in effect, and EST is only 4 hours behind UTC.
If the document was created in UTC time or the timezone is unknown, the time offset suffix might be missing altogether. A document created at the same time in a UTC time zone would show a date of 2022-08-30T14:33:00

RasterCommentMetadataType.Creator and RasterCommentMetadataType.Software seem a bit confusing because they both seem to represent the name of the software that created the PDF file. But they are slightly different:

Software indicates the program used to create the PDF file (presumably from another document).
Creator indicates the program that created the original document containing the information that is now in the PDF file.

For example, if the PDF Converter application generated the PDF file from a DOCX file created in Microsoft Word, then:

Software should be set to "PDF Converter v.w"
Creator should be set to "Microsoft Word x.y"

This information can also be obtained using RasterCodecs.ReadMetadataItems or RasterCodecs.ExtractXMPMetadata.

For more information about file comments, refer to RasterCodecs.ReadComment.

PDF File Comments

See Also

Reference