A salesperson told me that the U.S. government and its agencies prefer TIFF to PDF. Is that true?
No, that statement is false. The National Archives and Records Administration (NARA), the nation's official record keeper, responsible for storing not only business records from all branches of government and agencies like the SEC, but also rare documents such as original copies of the Declaration of Independence and the Constitution, is perhaps the best arbiter of the government's position on these two file formats, and it accepts both. Michael Carlson, the director of Electronic and Special Media at the Record Services Division at NARA, says both TIFF and PDF formats are equally acceptable to the administration, though he concedes that PDFs might be preferable to users in certain instances.
"There really isn't anything better for rendering a document the way it was created," says Carlson.
Alan Gilmore, a securities attorney with Lynch, Osborne, Theivakumar & Gilmore LLC, says, "The SEC is equally comfortable with the TIFF and PDF formats. There is absolutely nothing in SEC regulations or any interpretive guidance to suggest that the SEC favors one format over the other."
Which is more secure, TIFF or PDF?
While one could make the argument that neither format is 100% secure, the PDF format clearly has the advantage.
"TIFF files do not have any native security capabilities," says Larry Kovnat, a product security manager at Xerox. "PDF files do offer native security options."
Kevin Day concurs. "No part of the TIFF specification addresses security," Day says. The ISO PDF standard, by contrast, addresses both security and digital signatures. This means that when users need to secure a PDF file, they can use features of the PDF format itself to do so. You can use passwords and encryption on PDF files to restrict users from opening, printing and editing them.
Those who own a recent full version of Adobe Acrobat can create special PDF files called security envelopes, in which you can embed multiple documents. These envelopes are encrypted PDF files with attachments. This method allows you to transfer multiple documents without encrypting and password protecting each one individually. When the recipients open the envelope, they can extract the file attachments and save them to disk. The saved files are identical to the original file attachments and are no longer encrypted when saved.
We need to re-emphasize that neither format is inherently secure, but only the PDF format offers features that allow the user to password protect, encrypt and/or digitally sign files when necessary (for instance, when the user is transmitting files containing sensitive information via e-mail or on a CD). Not one expert I spoke with could suggest any circumstances when TIFF files are more secure than PDFs.
What about sustainability?
Some have suggested that TIFFs are preferable to PDFs because they were in use earlier and will continue to be used after PDF is gone. Again, this argument has no basis in fact. According to Carlson, the National Archives has no position on the sustainability of either format, though he expects both to be around for a very long time. The fact that the PDF specification is still being actively developed-and is part of the ISO standards body-indicates that it is here to stay and will remain "backward compatible" to communicate with older devices and standards.
At the same time, there has been no major revision of the TIFF specification since 1992. Furthermore, the TIFF specification does not explicitly define which compression algorithms are allowed, so some TIFF viewing applications might not properly read all TIFF files. For the long-term storage of their images, TIFF users are well advised to ensure that their files use only widely supported compression algorithms. This is especially true for the compression used for gray scale and color images.