File Formats and Sizes

UDSpace can accept almost any electronic file format, provided that the file is under 2 gigabytes in size. However, this does not mean that you should deposit material without considering whether you have chosen an effective file format and file size for it.

Though UDSpace can accept files up to 2 gigabytes in size, users must download files in order to access them. The larger the file, the greater the risk that the download might fail partway through. Consider using smaller file sizes, particularly if your intended audiences may not have high speed or reliable internet access.

The Library provides public dissemination for material deposited in UDSpace, helping that material stay available for reading and indexing in sites like Google Scholar and Google. While a file that you deposited in UDSpace will be downloadable years later, that does not guarantee that users will be able to view and use the file as originally intended. The software programs that were used to view the file may be no longer available or may be incompatible with current devices and operating systems.

While software and hardware may develop in unpredictable ways, we can say that some file formats have a greater likelihood than others of being usable in the future, with most or all of their functionality intact. We recommend using these file formats whenever possible (see current list below).

Besides recommending specific file formats, we also recommend file formats that have the following characteristics, which make it more likely that there will be more options for using and viewing files:

• Non-proprietary (i.e., not restricted to one company or vendor)
• Platform independent (i.e., able to run in multiple tools and platforms)
• No embedded files, programs or scripts
• No encryption
• No password protection

Recommended file formats for different types of materials

Spreadsheets: Use CSV or TSV if possible, or XLSX (Microsoft proprietary format, but widely supported). Avoid the older Microsoft XLS format, which has less storage capacity and is less widely supported.

Text: Use TXT, ODT, PDF, or PDF/A, or if necessary, Microsoft’s DOCX format. Avoid DOC, RTF, and WPD. If you are using PDF files, both formats are open and non-proprietary. The PDF/A file format is specifically intended for preservation, and will block certain features that make long-term preservation more difficult, such as linked or embedded fonts.

Images: Use PNG or JPG if possible; TIFF or JPEG 2000 as alternatives (TIFF and JPEG 2000 files may require special viewers). Avoid formats that originate in proprietary tools such as Photoshop or InDesign (PSD, INDD).

Audio: Use mp3 or mp4/mp4a files whenever possible, as they are efficient in terms of size and widely supported.

Video: Use mp4 whenever possible.

A note on audio and video formats in UDSpace: While audio and video files may be uploaded to UDSpace, in most cases, we do not recommend using UDSpace for audio and video. Audio and video files cannot be played from within the browser. They must be downloaded and played in another software program on the user’s computer. Large videos may be difficult to download depending on the strength of the downloader’s internet connection. If you want users to be able to play videos within an internet browser, consider whether UD Capture or an external service such as YouTube or Vimeo may meet your needs.