Cross platform issues by Matt Ottewill

The term "cross platform" primarily refers to data or media files which can be used or viewed on both Macs and PCs. For example, MPEG-1 video files will play on both Macs and PCs but PC AVIs can be problematic. Therefore MPEG-1 is a cross platform media format and AVI is not. In practise most file types are cross platform providing you observe the simple rules outlined on this page. Here are some examples ...

Yes No
.mov (QuickTime)
PostScript fonts
OpenType fonts
.swf (Flash)
.dcr, .dir (Director)
.txt, .rtf (text)
.doc (Word)
Cubase songs
MIDI files
.aif (audio)
.mp3 (audio)
.psd (Photoshop) etc
Logic projects
Final Cut Pro projects
Stuffit archives


When do we need to make files cross platform compatible?

The short answer is ... when you have to move files between, or view files on, PCs and Macs, such as when you make a web site.

Cross platform publishing concepts (optical media and web sites)

Click here for information on publishing projects including cross platform issues.

What are the primary cross platform issues?

There are several issues that you need to be aware of when making cross platform files.

ISO 9660 standard

The ISO9660 standard defines the file structure of a cross platform CDROM (PC and Mac).

Click here to read about the strict rules you must observe to ensure files are handled correctly by the widest number of PCs and Macs.

PC & Mac gamma differencies

Gamma is to do with screens and effects the way that computers display colour. For example ...

  • An image created on a PC will appear lighter and "washed out" on a Mac.
  • An image created on a Mac will appear darker and with "richer" colours on a PC.


Most computer users have a range of fonts installed but they don't all have the same fonts. This can change the way that your files (such as web pages and Word docs) appear when moved between computers.

To get around this problem you can do several things ...

  • Include fonts on a CDROM or a web site which a user must install on their system. BAD IDEA! Illegal and they probably won't bother.
  • Use fonts common to Macs and PCs such as Arial, Times, Courier and Verdana. Good idea but limits your designs.
  • Embed fonts in media files such as PDFs, images, Flash and Shockwave files. Click here for advice on this issue.