We asked ChatGPT about its support for PDF…

LibreOffice works to improve PDF/A and PDF/UA support

LibreOffice, a popular open-source office suite, is currently working to improve its PDF/A support as well as generating PDFs that are simultaneously PDF/A and PDF/UA compliant! As far as we are aware, LibreOffice 7.6.3 (the next version) will be the first office suite to achieve this! 

PDF and JDF - The Second Generation

The federal German Association of Printing and Media e. (Bundesverband Druck+Medien, BVDM) has published a trade press article (available in English) for the graphics art industry regarding the latest generations of PDF (PDF 2.0) and CIP4 XJDF (JDF 2.x).

BVDM has also published a German-language whitepaper “PDF 2.0 und PDF/X-6 – Was bringen die neuen PDF-Standards?” which is a good write-up from the prepress perspective to show the helpful improvements of PDF 2.0 for PDF/X-6, and also covers other standards like PDF/A and PDF/UA.

We asked ChatGPT about its support for PDF…

ChatGPT 4.0 is now able to consume PDF files. We wanted to know how well it supports PDF files. So, we signed up for the paid version, ChatGPT 4.0, and asked. Here’s the resulting conversation.

What version of PDF does ChatGPT 4.0 support?

ChatGPT 4.0:

ChatGPT, including version 4.0, generally supports analyzing text content from most common versions of PDF files. However, there are a few caveats:

• Text-Based PDFs: It works best with text-based PDFs rather than image-based ones. If a PDF contains only images of text, such as scanned documents, the tool might not be able to extract the text without an OCR (Optical Character Recognition) function, which is not natively supported in the current setup.
• Standard Features: It should handle PDFs that use standard features without issue. Some PDFs may have security settings that restrict copying text, and in these cases, the text might not be extractable.
• Non-Standard Fonts and Encoding: PDFs that use non-standard fonts or encoding might pose a problem if the system cannot correctly interpret the characters.
• Version-Specific Features: If a PDF uses very new or uncommon features specific to the latest versions of the PDF format (like certain types of embedded media or interactive elements), these may not be fully supported for analysis.

The core functionality for text extraction should work across various PDF versions, from the older 1.4 up to the more recent 2.0, as long as the text is selectable and copyable. If you have a PDF file and would like to have it analyzed, you can upload it, and I can demonstrate how the tool works with it.

Does ChatGPT 4.0 support PDF 2.0 files?

ChatGPT 4.0:

ChatGPT 4.0 can analyze text from PDF files, including those conforming to the PDF 2.0 specification, for tasks such as extracting text, summarizing content, and answering questions based on the text. However, it's important to note that this functionality is focused on text extraction and may not fully support all the advanced features introduced in PDF 2.0, especially those that pertain to multimedia, encryption, and interactive elements.

For typical use cases involving reading and interpreting the textual content of a PDF 2.0 file, you should be able to upload the file, and ChatGPT will do its best to process the content and assist you with your query. If you encounter any issues with specific features of PDF 2.0, those might be due to limitations in the current capabilities of the text extraction tools available to ChatGPT.

Does ChatGPT 4.0 consume document metadata (author, subject, keywords, etc) or object metadata in PDF files?

ChatGPT 4.0:

As of my last update in April 2023, ChatGPT does not inherently consume document metadata like author, subject, keywords, or object metadata within PDF files. Its primary functionality with regard to PDFs is centered around extracting and analyzing textual content. This means that while ChatGPT can read and interpret the text within a PDF file, it doesn't natively access or analyze the file's metadata.

For tasks that require analysis or extraction of metadata specifically, you would typically need specialized PDF processing tools that can read and interpret this information. In a standard setup, ChatGPT does not have the capability to directly interact with or extract such metadata from PDF files.

Does ChatGPT 4.0 consume PDF files containing right-to-left languages?

ChatGPT 4.0:

ChatGPT can process and analyze text from PDF files that contain right-to-left (RTL) languages, such as Arabic or Hebrew. However, there are a few considerations to keep in mind:

• Text Direction: ChatGPT's text processing capabilities should handle the RTL text direction, but the formatting might not always be preserved perfectly, especially if the text is mixed with left-to-right (LTR) content.
• Font and Encoding: The PDF must use a standard text encoding that ChatGPT can recognize. If the PDF uses custom fonts or encodings that are not widely supported, ChatGPT might have difficulty extracting the text correctly.
• Complex Scripts: RTL languages often use complex script features, such as ligatures and context-dependent character shaping. ChatGPT's ability to interpret these correctly depends on the underlying text extraction technology.

For simple text extraction and processing tasks, ChatGPT should be able to handle RTL languages in PDF files. However, for more complex formatting and advanced PDF features, there might be limitations. If you have a specific PDF file in an RTL language that you'd like to analyze, you can upload it, and I can help you with it to the best of the system's capabilities.

Does ChatGPT 4.0 support the ReverseChars tag in PDF files?

(The full prompt was: "ISO 32000-2:2020, clause 14.8.2.5.3 discusses reverse-order show strings, and specifies that "The marked-content tag ReversedChars informs the PDF processor that show strings within a marked-content sequence contain characters in reverse order. In order for such text to be extracted or read out aloud, the sequence of the characters as found in the show string operator shall be reversed before using them. If the sequence encompasses multiple show strings, only the individual characters within each string shall be reversed.")

ChatGPT 4.0:

As of the last update I received in April 2023, ChatGPT does not specifically support or interpret PDF structure or tagging conventions, such as the "ReversedChars" tag described in ISO 32000-2:2020 for handling reverse-order show strings.

The extraction of text from PDFs typically involves more straightforward processes that may not honor the more intricate tagging and logical structure features defined in the PDF specification. This means that while ChatGPT can read and process the text content of PDF files, it might not automatically recognize and correctly interpret the "ReversedChars" tag or other similar structural elements unless these features are integrated into the text extraction tool that ChatGPT uses.

For PDFs that use such specialized features, manual processing or the use of a dedicated PDF processing tool that fully supports the latest PDF specifications might be necessary to ensure accurate text interpretation.

Can ChatGPT 4.0 consume PDF documents containing horizontal and vertical Asian languages?

ChatGPT 4.0:

ChatGPT can analyze text from PDF documents containing Asian languages, whether written horizontally or vertically. However, there are a few important points to note regarding the processing of such documents:

• Font and Encoding: The PDF must use a standard text encoding that ChatGPT can recognize. If the PDF uses custom fonts or encodings that are not widely supported, ChatGPT might have difficulty extracting the text correctly.
• Text Direction: While ChatGPT is designed to process text in various languages, including Asian languages, the correct interpretation of text direction (horizontal or vertical) in the context of PDFs can be challenging. The underlying text extraction technology needs to handle such text directions accurately.
• Complex Characters: Asian languages may use complex characters that could be difficult to process if the document is not properly encoded.
• Layout Considerations: Asian scripts, particularly when written vertically, often have layout considerations that can affect text extraction. Text extraction tools may not always maintain the original layout or direction of the text.

In practice, for simple text extraction, ChatGPT should be able to handle text in Asian languages from PDFs. However, for more complex documents with mixed directions and advanced formatting, there could be limitations. If you have a specific PDF file containing horizontal or vertical Asian language text that you'd like to analyze, you can upload it, and I can assist you in processing it to the extent possible with the current capabilities.

Can ChatGPT 4.0 consume PDF documents containing multiple languages?

ChatGPT 4.0:

Yes, ChatGPT can process and analyze text from PDF documents that contain multiple languages. The system can extract text and then perform language detection to handle different languages within the same document. However, the accuracy and effectiveness of this process can depend on several factors:

• Text Encoding: The PDF must be encoded in a way that the text extraction tool can recognize all the characters from the different languages.
• Language Identification: Once the text is extracted, ChatGPT can typically identify multiple languages, but mixed-language documents may pose challenges, and there might be occasional misidentifications, especially with languages that share a script.
• Complex Formatting: If the document has complex formatting that affects the reading order or includes text in various directions (like vertical text in some East Asian languages), the extracted text may not always maintain the intended structure or order.
• Specialized Content: Some languages might use specialized or domain-specific terminology, which could be more challenging to process accurately without context.

For the best results with multi-language PDF documents, it's helpful to ensure that the document uses standard fonts and encoding, and to provide ChatGPT with clear instructions regarding what analysis or information is needed from the document. If you have a multi-language PDF file you wish to analyze, feel free to upload it, and specify your request for analysis or information extraction.

Can ChatGPT 4.0 leverage content semantics in PDF files as defined by PDF's logical structure and tagged PDF features?

ChatGPT 4.0:

As of my last update, ChatGPT does not inherently leverage the content semantics as defined by a PDF's logical structure and tagged PDF features, such as those that would be used by assistive technologies to understand the document structure (headings, paragraphs, lists, tables, etc.).

Tagged PDFs are meant to provide a layer of semantic understanding to the document that goes beyond the visual representation, including the correct reading sequence, alternative descriptions for images, and distinctions between different types of content. While this is crucial for accessibility and for applications that need to understand the structure of the content, ChatGPT's text extraction capabilities are generally focused on the textual content rather than the document's semantic structure.

This means that while ChatGPT can read and process the text within a PDF, it might not recognize and interpret the tags and structure that define the semantics of the content. For tasks requiring this level of detail, specialized PDF processing software with support for tagged PDF features would be necessary.

Does ChatGPT 4.0 consume Alt and ActualText entries on PDF structure element dictionaries or marked-content property lists for images, illustrations, figures, vector art, etc?

ChatGPT 4.0:

As of my last update, ChatGPT does not directly interpret or consume the Alt and ActualText attributes that are part of PDF structure elements or marked-content lists. These attributes are often used to provide alternative text descriptions for various types of content, such as images or figures, which is particularly important for accessibility purposes.

When ChatGPT processes a PDF file, it primarily focuses on extracting and interpreting the textual content. While it can analyze the text that is extractable from a PDF, it doesn't have the capability to recognize or utilize these specific metadata entries that would typically be used by screen readers and other assistive technologies.

For specialized tasks that require interpretation of Alt and ActualText attributes, dedicated PDF processing tools that fully support the PDF/UA (PDF for Universal Access) standard would be more appropriate. These tools are specifically designed to understand and utilize the rich semantics encoded in tagged PDFs, including alternative text for non-text content.

Does ChatGPT 4.0 consume PDF structure elements that specify natural language?

ChatGPT 4.0:

As of the last update I received, ChatGPT does not specifically consume or interpret PDF structure elements that specify the natural language of a document. The PDF structure elements that define the language are meant to improve accessibility and ensure correct language tagging for segments of text, which can be essential for screen readers and other assistive technologies.

When ChatGPT processes the text from a PDF file, it does so with a focus on the content rather than the metadata or tagging structure. It can detect different languages within the text based on the content itself, but it doesn't use PDF-specific language tags to inform its processing.

For processing tasks where the specific language tagging within a PDF is critical, dedicated PDF analysis tools that are designed to respect and interpret these tags would be necessary. These tools can provide more nuanced handling of multilingual and tagged PDF documents, ensuring that language-specific processing is applied as intended by the PDF's structure.

Does ChatGPT 4.0 ignore content in PDF files that is explicitly marked as artifact?

ChatGPT 4.0:

In the context of PDF processing, content marked as an "artifact" is typically decorative or redundant information that is not part of the meaningful content (like page numbers, headers, footers, or background images). These are often ignored by assistive technologies and when reflowing text for different display formats.

As of my last update, ChatGPT does not have the capability to distinguish and ignore content marked as artifacts within a PDF file. Its text extraction capability is based on extracting all text-based content from the PDF as presented, without the nuanced understanding of the document's tagged structure that would include artifact designation.

For scenarios where it's critical to differentiate between content and artifacts as per the PDF specification, specialized PDF processing tools are required. These tools can parse the PDF structure tags and respect the artifact markings to selectively process only the meaningful content.

Does ChatGPT 4.0 support or leverage MathML in PDF files?

ChatGPT 4.0:

As of my last update, ChatGPT does not support or leverage MathML within PDF files. MathML is a markup language that is used to display complex mathematical equations and symbols on the web and within digital documents.

ChatGPT's capabilities are centered around text extraction and natural language processing. It can extract and interpret text content from PDF files, but it does not have specialized functionality for recognizing or interpreting MathML or other markup languages beyond basic text.

For handling MathML content within PDFs, specialized software that understands and can render or process MathML is typically necessary. Such tools are designed to work with mathematical notation and would be required for tasks that need to interpret or manipulate the equations and formulas encoded in MathML.

Does ChatGPT 4.0 consume encrypted PDF files that do not require a password?

ChatGPT 4.0:

ChatGPT itself does not process files; it relies on underlying tools and APIs to interact with files, including PDFs. Encrypted PDF files that do not require a password typically use a form of encryption that restricts certain actions such as printing, editing, or copying text, but can be opened for reading without entering a password.

In general, if a PDF file is encrypted in a way that does not prevent opening and reading the file without a password, then the text extraction tool used by ChatGPT should be able to extract text from it. However, if the encryption restricts copying text, then the text extraction process might fail.

The capabilities of ChatGPT regarding encrypted PDFs would depend on the specific text extraction tool it uses and whether that tool can handle the encryption method applied to the PDF file. If you have an encrypted PDF file that you would like ChatGPT to analyze and it doesn't require a password to open, you can upload it, and I can attempt to extract text from it. If the encryption interferes with text extraction, then a specialized PDF tool that can handle such encryption may be necessary.

Does ChatGPT 4.0 OCR scanned PDF pages?

ChatGPT 4.0:

ChatGPT itself does not perform OCR (Optical Character Recognition) on scanned PDF pages. OCR is a process used to convert different types of documents, such as scanned paper documents, PDFs, or images captured by a digital camera, into editable and searchable data.

While ChatGPT can process and analyze text data, if the text is embedded in images within a PDF (as is the case with scanned documents), it would not be able to directly interpret this information without the help of an OCR tool.

As of my last update, OCR capabilities are not built into ChatGPT, and it would require integration with an OCR service or tool to convert images of text into machine-readable characters. If you have a scanned PDF that you need to analyze, you would typically need to run it through an OCR process first to convert the image-based text into selectable, searchable text before ChatGPT could be used to analyze the content.

ChatGPT 4.0:

As of my last update in April 2023, I don't have access to the specific internal details about the libraries or tools used by ChatGPT for extracting content from PDF files.

PDF in your crossword puzzle

The New York Times mini-crossword for October 19 considers “PDFs” as an “alternative to .doc files”.

No wonder trust in the media is declining! 🙂

PDFacademicBot for November 2023

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Changxu Duan, Zhiyin Tan, and Sabine Bartsch (2023) ‘LATEX Rainbow: Universal LATEX to PDF Document Semantic & Layout Annotation Framework’, Proceedings of the 2nd Workshop on Information Extraction from Scientific Publications, p. pp.56-67. Available at: https://ui.adsabs.harvard.edu/WIESP/2023/book.pdf#page=64.

Santhakumar, L. Sasikala, and A. Balajee (2023) ‘Book GPT: An Innovative PDF Querying Tool’, Chinese Journal of Computational Mechanics, (5), pp. 332–337. Available at: http://jslxxb.cn/index.php/jslxxb/article/view/4365 (Accessed: 14 October 2023).

Gusti, A.N.G.K.T.D., and Girinoto (August 2023) ‘PDFalse: Evasive Malicious PDF Machine Learning Classifier’, in 2023 IEEE International Conference on Cryptography, Informatics, and Cybersecurity (ICoCICs). 2023 IEEE International Conference on Cryptography, Informatics, and Cybersecurity (ICoCICs), IEEE, pp. 9–14. Available at: https://doi.org/10.1109/ICoCICs58778.2023.10277336.

Hinderliter, H. (2023) ‘On the Persistence of Pages’, in B. Hokanson et al. (eds) Toward Inclusive Learning Design: Social Justice, Equity, and Community. Cham: Springer Nature Switzerland (Educational Communications and Technology: Issues and Innovations), pp. 161–169. Available at: https://doi.org/10.1007/978-3-031-37697-9_13.

Jiang, S. and Li, Y. (2023) ‘Research and Implementation of PDF Specific Element Fast Extraction’, in 2023 4th International Conference on Big Data & Artificial Intelligence & Software Engineering (ICBASE), pp. 77–83. Available at: https://doi.org/10.1109/ICBASE59196.2023.10303081.

Khadija, M.A., Aziz, A. and Nurharjadmo, W. (October 2023) ‘Automating Information Retrieval from Faculty Guidelines: Designing a PDF-Driven Chatbot powered by OpenAI ChatGPT’, in 2023 International Conference on Computer, Control, Informatics and its Applications (IC3INA). 2023 International Conference on Computer, Control, Informatics and its Applications (IC3INA), IEEE, pp. 394–399. Available at: https://doi.org/10.1109/IC3INA60834.2023.10285808.

Liu, R. et al. (2023) ‘Research on a watermarking recognition method for PDF documents based on natural language processing’, in Fourth International Conference on Computer Science and Communication Technology (ICCSCT 2023), SPIE, pp. 150–155. Available at: https://doi.org/10.1117/12.3009389.

Medeiros, T. et al. (2023) ‘Analysis of Language-Model-Powered Chatbots for Query Resolution in PDF-Based Automotive Manuals’, Vehicles, 5(4), pp. 1384–1399. Available at: https://doi.org/10.3390/vehicles5040076.

So, J. et al. (2023) ‘How Small Businesses Transform PDF Agreements into Action’, in Companion Publication of the 2023 Conference on Computer Supported Cooperative Work and Social Computing. New York, NY, USA: Association for Computing Machinery (CSCW ’23 Companion), pp. 177–181. Available at: https://doi.org/10.1145/3584931.3606972.

Yamauchi, T. et al. (2023) ‘Automated labeling of PDF mathematical exercises with word N-grams VSM classification’, Smart Learning Environments, 10(1), p. 51. Available at: https://doi.org/10.1186/s40561-023-00271-9.