As of 1996, we said: "The following concerns file formats of interest to Macintosh users and conversions of a Mac document or application into/out of them."

As of late 2000, we say:
The file formats folder has been expanded to include items like RTF and Palm formats.  The master is on the work NT MM60395.

A conversion web site.

Formats

IPTC

The IPTC/NAA (International Press Telecommunications Council) and NAA (Newspaper Association of America) standard image information have a metadata model for associating additional information with all types of digital media. The IPTC standard has allegedly been widely adopted by the Digital Image Industry and within the Publishing and Printing Business. The IMatch Image Mangement software will embed EXIF into JPEG and probably other image formats.

EXIF

EXIF extends the JPEG format to allow image/digicam information data and a thumbnail image. An EXIF Editor was here: http://www.robophoto.com/exif.html but has been moved or deleted. The IMatch Image Mangement software will embed EXIF into JPEG and probably other image formats.

JPEG

The IPTC (International Press Telecommunications Council) in conjunction with the NAA (Newspaper Association of America) have a “JPEG File Information” standard for using the IIM Record 2 with caption text, et al., within a JPEG file. See the Adobe PhotoShop "File Info" option.



Formats of interest to Macintosh users. Well, in the "Mac rules" era (say 1984-92) that was the focus.

BinHex 4.0

BinHex 4.0 files are an encoding of Mac data, resource, and finder info into a "safe" stream of characters. On the Mac, the stream is in the data fork and the characters are each 8 bits. The 8 bit values are safe in the sense that they will be passed untransformed through every reasonable mail system. For example, the 8 bit characters can be cut to 7 bits (but later restored, when the file returns to a Mac), long lines (there aren't any) may be truncated, there are no embedded X-on, X-off, or other control characters, etc..

More here.

BinHex 4.0 files are usually denoted by the suffix ".hqx" (or .hqx7).

BinHex 5.0

BinHex 5.0 files are an encoding of Mac data, resource, and finder info into a stream of 8-bit bytes. On the Mac, the stream is in the data fork.
BinHex 5.0 is NOT a more advanced version of "BinHex 4.0" but rather a separate binary format (it uses the entire eight-bit ASCII character set and is thus not suitable for Usenet postings or e-mail)
BinHex 5.0 was the precursor to MacBinary.

BinHex 5.0 files are usually denoted by the suffix ".bin".

MacBinary

MacBinary is a standard way of representing a Macintosh file (resource fork, data fork, and other information (such as the filename, creation and modification dates, file type and creator) about the original file) into a stream of bits. On the Mac, the stream is in the data fork.

Dennis Brothers designed the original MacBinary standard many years ago. Yves Lempereur incorporated this standard intohis Binhex 4.0 program, solving a major problem on Compuserve. About a year later, around the time the Mac Plus came out, group discussions on Compuserve led to an enhancement of the original MacBinary standard. Since then, BinHex 4.0 and the newer MacBinary have become the standard way of encapsulating Macintosh files for transferring over foreign systems throughout the Internet, Usenet, and elsewhere.

MacBinary I is the name given to the old MacBinary standard. MacBinary II is the name given to the new MacBinary standard which everybody uses today; in common usage, MacBinary means MacBinary II.

Details here.

A MacBinary stream is a series of files in MacBinary format pasted together. Embedded within a MacBinary stream can be information about folders. So a MacBinary stream can contain all information about a folder and its constituents.

Like BinHex 5.0, MacBinary files are usually denoted by the suffix ".bin".

uuencoded

Every Mac-resident unix-to-unix encoded file is a stream of 8 bit characters representing a unix file (bitstream) plus a limited amound of associated unix directory information.

The uuencoding is "safe" in the sense that it will be passed untransformed through every reasonable mail system. For example, the 8 bit characters can be cut to 7 bits, long lines (there aren't any) may be truncated, there are no embedded X-on, X-off, or other control characters, etc..

The uuencoded file may have a different total number of bits depending on the type of computer to which it is transmitted, but it will always have the same number of characters.

Mac-to-Mac document transfer is to BinHex 4.0 encoding as Unix-to-Unix file transfer is to uuencoding.

Details here. UUdecoders here.

uuencoded files are usually denoted by the suffix ".uu".

MIME

MIME, the Multi-purpose Internet Mail Extensions, is the standard for how to send multipart, multimedia, and binary data using the Internet email system.

Details here. Mime FAQ.

MIME replaces UUENCODE.

There are a growing number of mail programs that have MIME support built-in. (One popular MIME-capable mailer for Unix, VMS and PCs is Pine, developed at the University of Washington and available via anonymous FTP from the host ftp.cac.washington.edu in the file /mail/pine.tar.Z)

There are a number of stand-alone programs that can interpret a MIME message. One of the more versatile is called "munpack". In short, mpack is the MIME equivalent of uudecode/binhex. It was developed at Carnegie Mellon University. There are versions available for Unix, PC, Mac and Amiga systems. Click here to get Mac version 1.5. For compabibility with older forms of transferring binary files, the munpack program can also decode messages in split-uuencoded format.

MIME References

The MIME Internet standard is described in RFC-1521. (A draft of another revision has been published.)

A Technical Overview of MIME

See Internet news group "comp.mail.mime", which includes a periodic posting of a "Frequently Asked Questions" list.

AppleDouble

AppleDouble is another means of storing Macintosh files on non-Macintosh computers or filesystems, particularly on Unix filesystems that also allow files to be mounted under the Macintosh operating system via AppleShare (or an equivalent product).

AppleDouble files are actually two files. The data fork of the corresponding Macintosh file is stored in a single file just as it exists on the Macintosh using the original filename. The resource fork is stored in a second file whose name is obtained by prefixing the original filename with '%'. More extensive documentation is available at ftp.apple.com.

Compressed Z

Files encoded with the UNIX program "compress" are usually denoted by the suffix .Z.

Compressed GZ

This format is similar to Compressed Z. Files encoded with the UNIX program "gzip" and decoded by the unix program gunzip are usually denoted by the suffix .gz. ( .gz indicates gzip [Lempel-Ziv] compression; .Z indicates ordinary [LZW] compression. )

PostScript (PS)

PostScript is a page description language - a programming language. A RIP, a Raster Image Processor, takes in PostScript code and renders it into dots on a page. A PostScript printer reads and interprets (using its RIP) PostScript programs, producing graphical information that gets imaged to paper, film, or plate. AGM - the Adobe Graphics Model used by InDesign® - is also a RIP: It actually processes the PostScript instructions and "prints" the results to the screen instead of to paper.

Encapsulated PostScript (EPS)

EPS files are commonly used for inclusion in other documents. Many single page PostScript files can be converted to EPS by changing the first line of the file to "%!PS-Adobe-3.0 EPSF-3.0" and then adding or fixing up the %%BoundingBox comment. But it is not possible to convert an arbitrary PostScript file to EPS. Adobe Acrobat Distiller is Adobe's ps to eps utility. 

Portable Document Format (PDF)

PostScript was designed to describe a page. PDF can also contain information not only related to how a page looks, but also can describe how it behaves and what kind of information is contained in the file. So PDF is a file format that is smarter than EPS. A PDF file can contain fonts, images, printing instructions, keywords for searching and indexing, job tickets, interactive hyperlinks, movies, and so on. A PDF file is actually a PostScript file which has already been interpreted by a RIP and made into clearly defined objects. (What the hell does *that* mean?!) Because these files are already interpreted by the RIP, they can be more reliable than an EPS or a .PS file when printed.

Ghostscript has "The ability to convert PostScript language files to PDF (with some limitations) and vice versa; " To convert a PostScript file to a PDF file, use GSView File>>Convert... and, after selecting the input .ps file, use the pdfwrite device to get the output .pdf file.

Stuffit 1.5 Archive

A format placing many Mac files into one.
To make things difficult, the extension .sit can refer to any of three completely different compression schemes: StuffIt 1.5, StuffIt 2.0, and StuffIt 3.0.

Stuffit 1.5 archives are usually denoted by the suffix ".sit".

Stuffit 2.0 Archive

A format placing many Mac files into one.
To make things difficult, the extension .sit can refer to any of three completely different compression schemes: StuffIt 1.5, StuffIt 2.0, and StuffIt 3.0.

Stuffit 1.5 archives are usually denoted by the suffix ".sit".

Stuffit 3.0 Archive

A format placing many Mac files into one.
To make things difficult, the extension .sit can refer to any of three completely different compression schemes: StuffIt 1.5, StuffIt 2.0, and StuffIt 3.0.

Stuffit 1.5 archives are usually denoted by the suffix ".sit".

Compact Pro Archive

A format placing many Mac files into one.
An archive can have many segments, each a Mac file. The last contains the archive directory.

Details here.

Compact Pro archives are usually denoted by the suffix ".cpt".

PackIt Archive

On very rare occasion, you may run across a .pit (PackIt) file. These archives were pioneers in Macintosh file compression and archiving, but today they're completely obsolete. StuffIt 1.5.1 and PackIt 3.0 will both uncompress .pit files, but PackIt is no longer supported, so it's unlikely that you'll see one.

PackIt archives are usually denoted by the suffix ".pit".

Shell Archive

A unix shell archive. Can be converted into text documents on a Unix system. Shell archives are usually denoted by the suffix ".shar".

Self Extracting Archive

This type of file is a double-clickable application that will automatically uncompress itself when launched.
A family of formats?

Self extracting archives are usually denoted by the suffix ".sea".

Apple DiskCopy disk image file

The Apple DiskCopy disk image file is typically used for distributing system software.
Apple DiskCopy disk image files are usually denoted by the suffix ".image".

MS-DOS PC archive (ZIP) file

The name says it.
MS-DOS PC archive files are usually denoted by the suffix ".zip". Details. Vendor

MS Office POI file

An interoperable file format designed for use with any Windows-based application.

File Suffixes

 The following file suffixes indicate formats that are native
 to the Macintosh and which can be manipulated using the indicated
 programs:
 .bin MacBinary files;
 .cpt Compact Pro archive files;
 .dd DiskDoubler archive files;
 .hqx BinHex files;
 .image Apple DiskCopy disk image file (typically used for
 distributing system software); latest version available
 via anonymous ftp from ftp.apple.com
 .pit Packit files;
 .sea Self-extracting archive files; this usually denote an
 application which can be double-clicked upon to create
 a decompressed version of the archive
 .sit StuffIt archive files;
 .sitd mistakenly used to indicate files created by StuffIt
 Deluxe; *all* StuffIt files should be given the .sit
 extension (says the author!)
 Table 2.5.2
 The following file suffixes indicate formats that are not native
 to the Macintosh, but in most cases, files of these types can
 be manipulated on the Macintosh using the indicated programs.
 .arc MS-DOS PC archive file; ArcPop, MacArc
 .arj MS-DOS PC archive file; unArjMac
 .gif Compuserve Graphics Interchange File; many programs,
 free, shareware and commercial exist to display and/or
 modify these images; some of the popular shareware ones
 are: QuickGIF and GIFConverter.
 .lzh MS-DOS PC archive file; LHarc or MacLHa
 .shar Unix shell archive file; Unshar 1.5
 .uu Unix uuencoded files; see [2.3]
 .Z Unix 'compress' archive file; MacCompress 3.2
 .zip MS-DOS PC archive file; UnZip, ZipPop
 Table 2.5.3

Audio & Video Formats

Multimedia

The impact of IP on File Formats: Next Generation

Conversion Utilities

Extracting/Decompressing/Downloading to Mac Native Format

Known to work: folderWithStuff.hqx -> Stuffit Expander 3.5.2 -> a folder with stuff iWantIt.sea.hqx -> Stuffit Expander -> iWantIt Note: In the table below, a W indicates an entry I found but think is wrong. A indicates something I added.

 Suffix: .sit .cpt .hqx .bin .pit .Z .image .dd .zip .uu .tar
 Extractors
----------------------------------------------------------------------------
StuffIt 3.0 | X X X X X X X ! ! !
$ Expander | X X X
Compact Pro | X X
UULite 1.4 | X
MacCompress | X
SunTar | X X X X
BinHex 5.0 | X
BinHex 4.0 | X
BinHqx 4.0 | X
DiskDoubler | X
UnZip | X
DiskCopy | X
Packit | X
 Table 2.5.1
 ! Note: StuffIt Deluxe 3.0.3 includes translators for .tar, .uu,
 MacBinary, atob, btoa, AppleLink packages, AppleSingle, DiskDoubler,
 and Unix compress. These translators can also be used with StuffIt
 Lite. .arc and .zip translators are also distributed with StuffIt
 Deluxe, but remain part of the commercial package.
 $ 'Expander' refers to Stuffit Expander 3.0 which can decode BinHex,
 Stuffit, Compact Pro, and Applelink archives. It supports drag-
 and-drop under System 7. Stuffit Expander is distributed free by
 Aladdin Systems Inc.

Compressing/Archiving/Uploading from Mac Native Format

TBS

Either Compressing or Decompressing

Refs can be found here here here here and here.

Downloading

The downloading process is described here, here, here, or here.

What the Mac application Fetch does is described here.

General References

MacUser Guide to Shareware (1998/06: This URL is obsolete)

File formats, compression, and archiving May 1993.

UTexas compression page.