Patent Center PDF Guidelines

PDF Guidelines

The USPTO will be receiving electronic patent application documents in the Adobe PDF (Portable Document Format) format, from which images will be produced for the Image File Wrapper (IFW) system. Because the PDF format is so feature-rich, a standard is required to restrict submitted content to what the United States Patent Office is prepared to receive. The following guidelines set forth in this document will help to ensure that the created PDF documents meet the requirements for processing at the USPTO.

The following guidelines are based in part on the PDF/A specification; a document conforming to PDF/A will meet the requirements of Patent Center for submission to the USPTO.

Document Formatting

The page size should be either 21.0 cm by 29.7 cm (DIN size A4) or 21.6 cm by 27.9 cm (8.5 by 11 inches). Pages of a larger size will be reduced to 8.5 by 11 inches, which may affect readability of the document and/or distort any attached image.

PDF Version

The PDF document must conform to any one of versions 1.1 through 1.6 of the Adobe PDF specification. These are the versions supported by the USPTO reference viewer (Adobe Acrobat Reader version 7.0 or higher). This document will be revised to indicate support for any future versions of PDF. A review of the to-be-filed document(s) is strongly recommended before submission.


All characters (glyphs) that make up the text of the document must be embedded. Embedding allows the fonts used in the creation of a document to travel with that document, ensuring that a user sees documents exactly as the designer intended them to be seen. Embedded fonts may be limited to a subset containing the glyphs necessary to render the document. All fonts embedded within the document must be licensed and legally embeddable.

Color Text

It is recommended that the text of the document be black. Text of other colors may not convert to image properly, resulting in unreadable or invisible text.


Bi-tonal (black and white), color, or grayscale images should be scanned at a minimum resolution of 300 DPI.

It is recommended to use images saved in a lossless format (e.g., TIFF, PNG, GIF, BMP). It is strongly recommended that the PDF creation software does not downsample images during the PDF creation process, as this could degrade the quality of the image. For color and grayscale images, it is recommended that no compression be used; CCITT Group IV compression is recommended for bi-tonal images.

The use of Alternates (a feature within PDF that allows for alternate images to be used for on-screen rendering and printing) is prohibited.

Images consisting of multiple layers must be flattened before embedding into the PDF document. The properties of all layers should be marked as "visible" before flattening. This ensures that the complete image is visible to the examiner.


PDF documents with multiple layers must be flattened prior to submission to ensure that the complete document is available to the examiner. If a document contains layers that are marked as "invisible", the invisible layers will be lost when the received document is processed within the USPTO. Documents submitted with multiple layers will be flattened by the USPTO when converted to an image.

Object Content

Content that cannot render (be viewed) directly or completely to a printed page, including: multimedia (e.g., sound, video, animations, slideshows), 3-dimensional models (e.g., CAD drawings), file attachments, multi-page objects (e.g., Microsoft Excel spreadsheets, multi-page TIFF images), and commenting/reviewing features (highlighting, annotations, comments, notes, and the like) are prohibited.

There must be no dependencies on external files or resources of any type in order to render the attached image.

Security Features

Password protection and encryption are prohibited. Documents that are protected in this manner will not pass validation, thus will not be submitted. When files are submitted through Patent Center, the SSL v3 / TLS v1 protocol within the TruePass security application will provide the needed security and protection.

Embedded Code/Viruses

The PDF document must be free of executables, worms, viruses, or any type of potentially malicious content. Any files that found to have potential malicious content will be deleted.

Read " Files that can be submitted " for instructions on allowed file types and file naming requirements.