There is a seminal paper by Eduard Imhof on the correct placement of point, line, and area labels titled Positioning Names on Maps. If you haven’t already read and studied this paper, then this is something to be put at the top of your list if you ever do label positioning.
One brief passage in the paper discusses the idea that spreading a label across a large area may create an unintended heaviness to the label. If your label has a large amount of character spacing and you do not want it to appear as though it is at the top of the labeling hierarchy, he suggests using an openface font. To test this idea, I’ve installed the free font called Cloister Open Face (available here). There aren’t a lot of openface fonts available and they are certainly not widely used.
Testing the font on an existing map yielded the following. Please note that this map shows rough boundaries of the axis and allied powers as they stood at the very beginning of World War II — they are not the current political boundaries. I’m using this map simply for illustrative purposes and because it happened to be at-hand this morning.
Label changed to Cloister Open Face Regular
Indeed, it does certainly seem as though the open face font allows the type to be spread out across a large area without drawing as much attention to it as with a regular font. This does show that it is a technique that needs to be in your mental file. However, do realize that it is not a commonly seen technique. Much more common is to simply downgrade the font’s color from a bold black to, say, a medium gray. In the examples above, a medium gray produces a cool-on-warm “dizzy” effect so the following example only reduces the black by 20%. However, it still achieves a bit of a lightening of the weight when compared with the first, completely black, example.
Relevant label-types for this technique include mountain ranges, national parks, and wilderness areas, to name a few. Remember, if you are working with a map that has a light background (i.e., not like the examples in this post), you may want to try a bold light-gray font color instead of an openface font. As always, experiment yourself and determine what is best for your particular map subject and style.
If you like this post, you might also like Type Tips II.