Graphics which originate on Macintosh computers can be difficult to read on a Windows-based system, depending on which application created them and how they made the transition from the Macintosh environment.

Graphic Workshop Professional has been designed to detect Macintosh graphic issues and work around them.

There are two common problems in accessing graphic what have originated on a Macintosh system, as follows:

PICT files: The common graphic file format on a Macintosh is PICT. Most Macintosh graphic software can work with PICT – almost nothing under Windows can. Storing graphics in PICT files makes them difficult to access for non-Macintosh users.

Graphic Workshop Professional will read PICT files which store images, allowing you to view them and convert them to more common formats.

Macintosh computers do not identify file types using file extensions in the way Windows systems do. Graphic Workshop expects PICT files to have the extension PCT. You might have to rename suspect files in make them confirm to this naming convention.

The PICT format can be used to store graphic information other than images, and Graphic Workshop can't read these. This having been said, other sorts of graphics – essentially line drawings and commercial art – rarely turn up in forensic investigations.

MacBinary Headers: Back in the early history of telecommunications, Macintosh users needed a way to exchange files over early computer "bulletin board" systems. The Macintosh file structure doesn't allow for this as it stands, and the programmers of the time created a "header" to precede Macintosh files to be uploaded. The header tells a receiving Macintosh how to turn a downloaded file back into the unique Macintosh file it started out as.

This "MacBinary" header is still used in some circles, and perhaps more to the point, can be employed to make otherwise normal graphic files appear to be corrupted if they're viewed on Windows-based computers.

As an example, software which reads GIF images will look for the six characters "GIF89a" as the first six bytes in a GIF file. If it doesn't find this identifying string, it will assume that the file it's been given to read isn't a GIF file, and refuse to proceed.

If the GIF file in question includes a MacBinary header, a Windows-based GIF reader will see the MacBinary header, rather than the start of a GIF file, and decide that the file is unreadable.

Graphic Workshop Professional has been designed to look for MacBinary headers in those formats where they appear, and skip past them to find the real files that follow them. In most cases, you won't even know it's doing so unless you query its file information function.

You can effectively remove the MacBinary headers from graphic files – making the graphics in question readable by other Windows imaging software – by having Graphic Workshop convert from the files in question to any other format you like, such as BMP, PNG or JPG.

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