Master Jasper Greensmith of the Seagirt Glen, Dame Zenobia Naphtali, and Lord Torric inn Bjorn© Glen Fisher, Leslie A. Schweitzer, and Floyd Bullock (12/1/92)
Your heraldic device (informally, your "coat of arms") is essentially your personal "logo," and identifies you the way a company's logo identifies the company. On a banner, it tells everyone you're at an event. On a shield, it tells who's on the field fighting. On tableware, it tells whose place it's at. On clothing, it tells who's in the clothing.
The heraldic device originated in war. During the chaos of battle, you had to decide within seconds whether someone approaching was friend or enemy. The device evolved to allow this; painted on a shield, it told who was behind that shield. It was so helpful for identification during war that it soon spread into peacetime use as well.
Since a device identified the man who displayed it, it was very important that no two men have the same device. Colleges of Arms came into being to resolve conflicting claims on a device, and the heralds gradually assumed the job of keeping track of who owned which device. In the S.C.A., we have our own College of Arms to insure that each member has his or her own unique device.
A heraldic device is made of a number of charges (objects, creatures, or geometric shapes) arranged on a field (or background). Ideally, the result is simple, memorable, and easily identified. To help you create a good device, the heralds restrict the possible colors, poses, and arrangements of charges in your device. they do not restrict the objects or creatures you can choose from (except that you may only use period objects or creatures). Nor do the heralds care what artistic style you draw your device in, as long as the style was used in the heraldry of some place or time. You can, for example, use the smooth cat-like lions of the 12th century, the wild-haired lions of the 15th century, or the naturalistic lions of the late 16th century.
Good devices have as few charges and colors as possible. The best devices fill the roughly triangular shield with one or three identical charges, and use only two colors (examples 1 and 2). More often, you'll have to use more than one kind of charge, or more than two colors. Even then, you should use as few kinds of charges (and as few of each kind) as you can, and no more colors than you must.
Good devices repeat themselves. If the same kind of charge appears three places, all three are identical. They're the same color, in the same pose, and facing the same direction (examples 2-4). "Mirror imaging," with charges that face one another, is a modern style; it wasn't used in medieval heraldry.
Good devices make it easy to identify each charge. Animals are posed to show as much of the animal as possible (examples 1 and 4). Other charges are drawn to make them as distinctive as possible. And all charges are drawn as large as possible while still fitting in the space available.
Finally, good devices have high contrast between their parts. As much as possible, light charges (white, silver, yellow, or gold) are put on dark fields (red, green, blue, purple, or black), and vice versa. (Traffic and street signs all do this, to be as easy as possible to read.)
When you design your device, always work with your local or Kingdom heralds. They're there to help you, and they're happy to do so. They know the rules, and they know how to design good devices. As well, they can show you various charges you can use. When you're ready, they can even make sure your device is different from any other device in the S.C.A.
Get together with your herald and his books, or drop by a "Heraldic Consultation Table" at any event which has one.
Once your device looks legal and unique, make sure you like it. Put it up on your refrigerator, or in your office, for a few weeks. If you're still as happy with it afterwards, give it to the heralds to begin the process of "registering" it, so it can be uniquely yours in the S.C.A.