PDF/A White Paper PDF/A-Support in Compart Products White Paper compart Compart Systemhaus GmbH Otto-Lilienthal-Str. 38 71034 Böblingen Tel. +49 70316205-0 www.compart.net
PDF/A Support in Compart Products II Copyright 2006, 71034 Böblingen Otto-Lilienthal-Str. 38 Tel. +49 7031 6205-0 Fax: +49 7031 6205-55 www.compart.net e-mail: info@compart.net 1 st Version () Compart is registered trademark of the. All rights, even partial reprints, copies (incl. Microcopies or electronically processed copies) as well as analyzing this document with databases or similar environments are reserved. The document in hand is for information only. Even though all the information has been gathered with great care, misrepresentations cannot be excluded. Please do not hesitate to inform us of any mistakes or inaccuracies.
PDF/A Support in Compart Products III Preamble This whitepaper contains general information about PDF/A and also describes how PDF/A is supported in Compart s products and the PDF/A validation profile. Further Reading PDF Reference Third Edition Adobe Portable Document Format Version 1.4 ISO/PRF 19005-1 Document management Electronic document file format for long-term preservation Part 1: Use of PDF 1.4 (PDF/A-1) Trademarks Registered trademarks of other manufacturers are fully acknowledged as protected trademarks of their owners.
PDF/A Support in Compart Products IV Table of Contents Preamble... III Further Reading... III Trademarks... III Table of Contents...IV List of Tables...V 1. PDF/A General Information...1 1.1. PDF/A and Levels of Conformance...2 2. Compart Products and PDF/A...3 3. The PDF/A-1b Standard...4 3.1. Compart and PDF/A-1b...5 4. PDF File Validation...9 5. Adobe and the ISO Standard...10
PDF/A Support in Compart Products V List of Tables Table 1: Main Features of the PDF/A-1b Standard...5 Table 2: Features of the PDF/A-1b Standard...6 Table 3: PDF/A-1b XMP Metadata...8
PDF/A Support in Compart Products 1 1. PDF/A General Information In September 2005 the International Standards Organization (ISO) approved a new standard for document archiving. The full title of the standard is: ISO 19005-1, Document management Electronic document file format for longterm preservation Part 1: Use of PDF 1.4 (PDF/A-1). The reason for a new standard: In the past none of the document formats among the so-called CI formats (Coded Information), based on its specifications and widespread use, seemed suitable for processing the long-term archival of output documents. CI formats are capable of describing all visible content such as text, picture files, vector graphics, fonts as well as color spaces in coded form. But in contrast to raster formats such as TIFF, JPEG, or GIF, text in CI formats are not in raster form but held as coded text which may also be used to find text segments. This is not possible for documents in TIFF format, which due to the widespread use and support of this format was used in the majority of archiving systems. Rendering output documents in raster format causes the loss of all text information since the text is converted to a pixel image. PDF however developed by Adobe specifically as an exchange format is ideally suited to transfer documents easily from one platform to another. Unfortunately compatibility over more than two versions of PDF was not guaranteed. Therefore it was not possible to assume that that documents converted to PDF could be viewed with the latest PDF viewer such as Acrobat Reader after a number of years. On the other hand, because of its wide adoption in contrast to other CI formats, PDF with some additional standardization was considered more suitable as a longterm archiving format. It was with this in mind that AIIM (Association for Information and Image Management) and NPES (National Printing Equipment Association), together with Adobe and with encouragement from several government departments, users and PDF suppliers began an initiative mid 2002 to define an appropriate standard based on PDF. The result of these efforts is PDF/A.
PDF/A Support in Compart Products 2 1.1. PDF/A and Levels of Conformance The PDF/A standard is divided into in PDF/A-1 (Part 1) and PDF/A-2 (Part 2). PDF/A-1 is further classified in PDF/A-1a and PDF/A-1b. The PDF/A-1b (Level B Conformance) standard describes the minimal requirements of the PDF/A standard, required for long-term archival. PDF/A-1a and PDF/A-1b are differentiated largely in respect to text extraction. PDF/A-1a guarantees that the logical structure of a document as well as the reading order is preserved. Text extraction is important when documents may need to be displayed on a Personal Digital Assistant (PDA) or another (similar) device 1. In this case the text has to be re-ordered on the limited display area available (Tagged PDF). Herein lies the difference with the PDF/A-1b standard, which guarantees that text can be properly displayed, but not that it is readable or understandable. Compart Products initially support the PDF/A-1b standard on the output side. 1 See section 508 of the US Rehabilitation Act.
PDF/A Support in Compart Products 3 2. Compart Products and PDF/A DocBridge Mill, apart from its other features is also a fully fledged COLD product for the preparation of document datastreams as individual documents ready for archiving including index extraction. With this feature it is possible to make the output datastream PDF/A conformant and to pass it directly as the input to any archive system: AFP, AFP Mixed Mode, PDF, PCL, Xerox LCDS, and Metacode with DJDE, SAP ALF and OTF, ASCII and EBCDIC Linemode, Lotus Notes CDR, RTF, WMF, and the raster formats TIFF, JPEG, BMP, GIF, PNG, TGA, and DjVu. In addition Compart s Application Renderer via its internal print driver can prepare PC documents and Notes mail databases as PDF/A files.
PDF/A Support in Compart Products 4 3. The PDF/A-1b Standard The PDF/A specification is based on PDF version 1.4, and as part of this specification, it designates additional criteria which have to be met. These mostly concern the restriction of features allowed in PDF V1.4 but not in PDF/A. While PDF/A deals with the static, image character of a document, all interactive elements within the document such as JavaScript are forbidden. Apart from this PDF/A documents may include device-independent color spaces, written with the help of ICC profiles. However, they may not also include device-dependent color spaces (CMYK and RGB). Furthermore passwords are taboo, as are compression methods for which the licensing conditions cannot be established beyond any doubt (i.e. LZW). All fonts, including the 14 standard fonts must be embedded. Note: All features of PDF version 1.4 are allowed, unless they are specifically prohibited by PDF/A-1b.
PDF/A Support in Compart Products 5 3.1. Compart and PDF/A-1b At the moment it is not possible to produce PDF/A-1b, neither by a 1-to-1 copy (binary copy) nor by using an appropriate stamp. If files have to be created according to the PDF/A-1b standard, there are two ways of doing this: Using the strict mode (production) produces the PDF/A-1b standard. If certain conditions cannot be fulfilled, processing will either be halted with an error message, or an attempt made to meet the condition matically. The normal mode (verification) is used to create a document which fulfills the PDF/A-1b standard. For features not part of the standard, an error message is output. The following table details the implementation in Compart s software products of the main features of the PDF/A-1b standard. Table 1: Main Features of the PDF/A-1b Standard Feature Description Encryption Metadata Fonts Color Spaces Annotation Forms Encrypting documents is not allowed. Passwords as well as restrictions such as document printing, editing, etc may not be specified. The following metadata are matically added as XMP data: Title, Creator, Subject, Creatortool, Producer, Createdate, and Modifydate. All fonts must be embedded in the document. All fonts are checked. Only one uniform color space is allowed. RGB and CMYK color spaces are supported. An matic color space conversion is done, client specific color spaces may be used, if these conform to the specific requirements. Only ICC profiles conforming up to the ICC specification version 4 may be included. Data, sound, and video attachments are not allowed. The visual presentation is retained, any interactive objects are removed. Mode Message Strict Normal Abort Warning Any encryption is removed. -- -- -- Transparencies Transparencies are not allowed -- -- Abort Error Message Fonts cannot be embedded. Abort Warning a) Color Space conversion was done. b) Customer profile may not be used. Abort Warning Attachments are removed Abort Warning
PDF/A Support in Compart Products 6 The following table lists additional features of the PDF/A-1b standard and how they are implemented by Compart. Table 2: Features of the PDF/A-1b Standard Feature Description EmbeddedFiles entry in the Names dictionary Encoding entry prohibited for symbolic TrueType font Encrypt key present in file trailer ID in file trailer missing or incomplete Metadata not embedded as plain text Metadata does not conform to XMP The EmbeddedFiles key is prohibited in the Names dictionary in the Catalog dictionary of a PDF/A file. PDF/A prohibits that symbolic TrueType fonts uses the Encoding entry. The use of the Encrypt key in the file trailer (and thus the use of encryption) is prohibited for PDF/A files. The ID entry in the file trailer must be present and must contain two hex strings. PDF/A requires that the Metadata dictionary does not contain the Filter key, which in essence means that it must be embedded as plain and therefore decompressed text. PDF/A requires that the Metadata of a PDF document conform to the XMP specification. Alternate image present The image has an alternate image associated with it. Device process color used PDF/A requires that as soon as DeviceGray, DeviceRGB but no OutputIntent or DeviceCMYK are used an OutputIntent CMYK used but OutputIntent not CMYK CMYK used for alternate color but OutputIntent not CMYK RGB used for alternate color but OutputIntent not RGB Gray used but wrong destination profile in OutputIntent Gray in alternate color space but wrong destination profile in OutputIntent Uses DeviceRGB Device process color used in alternate color space but no OutputIntent ICC profile with a destination profile must be present. Use of DeviceCMYK is prohibited by PDF/A if the OutputIntent does not contain an CMYK destination profile. Use of DeviceCMYK is prohibited by PDF/A if the OutputIntent does not contain an CMYK destination profile. Use of DeviceRGB is prohibited by PDF/A if the OutputIntent does not contain an RGB destination profile. Use of DeviceGray is prohibited by PDF/A if the OutputIntent does not contain a Gray, RGB, or CMYK destination profile. Use of DeviceGray is prohibited by PDF/A if the OutputIntent does not contain a Gray, RGB, or CMYK destination profile. Use of DeviceRGB is prohibited by PDF/A if the OutputIntent does not contain an RGB destination profile. PDF/A requires that as soon as DeviceGray, DeviceRGB, or DeviceCMYK are used an OutputIntent with a destination profile must be present. ICC profiles version 4 or newer are prohibited in PDF/A. Compart Implementation Output Message See Table 3: PDF/A-1b XMP- Metadata on page 8. checked ICC-profile is not valid, wrong version, version < 4 Destination profile missing PDF/A requires that an OutputIntent contains a destination in OutputIntent profile. Interpolate key for image PDF/A requires that the Interpolate key for an image - not false if present - must be set to false. CIDSystemInfo and CMap PDF/A requires that CIDSystemInfo and CMap dictionaries dictionary not compatible be compatible. File size is larger than 2GB Support for PDF file sizes beyond 2GB. checked File size is larger than 2GB. Stream object contains F entry The use of the F key is prohibited in PDF/A.
PDF/A Support in Compart Products 7 Table 2: Features of the PDF/A-1b Standard Feature Description Compart Implementation Output Message Stream object contains The use of the FDecodeParams key is prohibited in FDecodeParams entry PDF/A. Stream object contains The use of the FFilter key is prohibited in PDF/A. FFilter entry Document contains JavaScripts JavaScripts are an advanced feature in Acrobat to add interactivity to PDF pages as well as to form fields. JavaScript objects are removed. PostScript operator used PDF/A prohibits the use of embedded PostScript. PostScript XObject used PDF/A prohibits the use of embedded PostScript. Has EF (embedded file) Has EF (embedded file) entry. entry Glyph in subset font missing PDF/A requires that a font subset contains all glyphs used in the page description. Form field does not have PDF/A requires that every interactive form field has an appearance dictionary appearance dictionary. NeedAppearances flag present PDF/A requires that an interactive form field either but not set to false does not have a NeedAppearances flag or that it is set to false. Info does not match Metadata according to PDF/A Info does not match Metadata according to PDF/A. Prohibited annotation type PDF/A prohibits the use of annotations with a type of FileAttachment, Sound, or Movie. File Attachments, Sound, and Videos are removed. Annotation NoView flag set PDF/A requires that the NoView flag for an annotation is not set. Annotation Invisible flag set PDF/A requires that the Invisible flag for an annotation is not set. Annotation Hidden flag set PDF/A requires that the Hidden flag for an annotation is not set. Annotation not set to print PDF/A requires that all annotations are set to print. LZW compression used Due to patent and licensing issues LZW compression is prohibited in PDF/A. Max. number of colorants PDF/A-1 allows a maximum number of colorants of 8 n.a. for DeviceN exceeded in a DeviceN color space. PDF/A label missing PDF/A label missing. Font not embedded PDF/A requires that all fonts used be embedded. checked Fonts are checked, if embedding is allowed. Page description uses invalid operator Type 2 CID font: CIDTo- GIDMap invalid or missing PDF/A prohibits the use of operators in a page description if they are not defined in PDF 1.4, even when they are bracketed by BX...EX. PDF/A requires that a Type 2 CIDFont has a stream mapping from CIDs to glyph indices or the name Identity as its value. Incorrect PDF/A version Incorrect PDF/A version number (must be 1). number Invalid WMode PDF/A requires that WMode in CMap dictionary be identical to WMode in CMap stream. Incorrect PDF/A-1b conformance Incorrect PDF/A-1b conformance level (must be "B"). level Wrong encoding for nonsymbolic PDF/A requires that non-symbolic TrueType fonts use TrueType font MacRomanEncoding or WinAnsiEncoding. Uses named action with a PDF/A requires that a PDF uses no actions except the value other than standard page navigation named actions NextPage, PrevPage, FirstPage, and LastPage. Uses layers Uses layers.
PDF/A Support in Compart Products 8 Table 2: Features of the PDF/A-1b Standard Feature Description Compart Implementation Output Message Uses JPEG2000 compression Uses JPEG2000 compression Uses scaling factor Uses scaling factor Uses transfer curve PDF/A prohibits the use of transfer curves. Uses transparency PDF/A prohibits the use of partial transparency. checked Transparencies are removed. Uses additional actions (AA) PDF/A prohibits the use of additional actions. The following table contains the XMP Metadata used by Compart. Table 3: PDF/A-1b XMP Metadata Element XMP Type Description dc:title Text Title dc:creator Text Author dc:subject Text Subject dc:keywords Text Keywords dc:creatortool Text Created with... dc:producer Text Producer dc:createdate Date Creation date dc:modifydate Date Modify date
PDF/A Support in Compart Products 9 4. PDF File Validation Currently, Adobe Acrobat Professional 7.0.7 is available to validate if a PDF document complies with the PDF/A-1b standard. This can be done in the following way: Open the PDF document. Advanced Preflight. The Preflight window will be opened Select "Conform with PDF/A". Execute. Errors will be shown in the window. Please note that only Adobe Acrobat 7.0 Professional Version 7.0.7 includes the up-to-date profile for PDF/A-1b validation. Based on information from callas software GmbH (developer of amongst others the software for PDF validation, including a module used by Adobe), the PDF/A-1a (including structure information) is at the moment not supported.
PDF/A Support in Compart Products 10 5. Adobe and the ISO Standard Currently Adobe Acrobat uses a name space to create and validate PDF/A-1b, which is not compliant with the ISO 19005-1 standard, while Compart does conform to the ISO standard to create PDF/A-1b files. This means that the error message PDF/A Label missing is produced when PDF/A-1b files are validated. The error can be remedied in the future by Adobe with a program update.