Why are Apple Macs used so much in the graphic design industry?

There’s a seperate question on which is better: Are Macs preferable to PCs for handling graphics software?

For the question of why Macs are more popular, there’s a very simple answer:

• Almost all art colleges and design schools bought Macs back in the days when Macs were unquestionably better for design (Alan G’s and Horatio’s answers below detail how)
• Art / design teachers got used to teaching using Macs. Many top teachers are veterans of the pre-computer days, and would not willingly suffer learning a new operating system
• So, most designers use Macs in their formative college years, and get used to Macs

Art/design colleges are unlikely to change to PC-first as it would be expensive and difficult (not just the cost of buying new machines, but the cost and time of re-training staff and re-writing course materials, and the cost in popularity among senior staff for whoever made the decision…). Many do now have PC suites as well as Mac suites, but they’re usually smaller and linked to specialist areas (e.g. video/games/fx design, John’s answer below explains why).

Designers are seldom keen to change tools. We’re not techies, our tools are a means to an end – “if it ain’t broke don’t fix it”. We usually have a similar attitude to technology as musicians have to the craft of making instruments – “magic happens here – don’t mess with the magic you need to do your job”.

(there are many exceptions – e.g. designers who write scripts, like there are musicians who make their own instruments – but they are exceptions, and the reaction to both is often similar: “What dark sorcery is this…” with a mixture of awe and suspicion)

So, most designers prefer to stick to the tools they know, which will more often be a Mac.

You could make a Windows machine that is 100% designed for designers, like the Wacom Mobile Studio range, for example – but when any crafts professional knows that their existing way works and is considered normal and correct, they usually won’t want to risk invoking the wrath of the Technology Gods, smiting them with the curse of “It fails when you need it the most!” for deviating from the familiar, true path. It is known.

These days, familiarity, comfort and preference are a bigger factor than any objective difference between Mac and PC, and PCs seem to be becoming slowly more popular in design than they were as more people start design school having already done design on a PC. I personally use a Mac at work and a PC at home, and the practical differences are tiny.

If you’re already comfortable with one, there’s no real reason to switch, unless you fancy a type of machine that is only available to the other (e.g. Windows pro pen tablets like MS Surface Pro or Wacom Mobile Studio, or, easy resolution toggling on retina Mac screens for testing). If you do, there’s no real reason not to switch, so long as you don’t mind re-learning a few things and risking a little frustrating unfamiliarity at first.