By Alex Richards
While the last article discussed what to colour, today I'll be discussing which colours to use. Here the choice essentially comes down to whether to use an existing colour scheme, or to create your own, and in the case of the latter, how to do so.
Using an Existing Scheme
Perhaps the simplest colour scheme to use is that of the map you're tracing from. This has the distinct advantage that most commercial maps tend to have been through a lengthy design process to ensure a good colour balance and distinct shades, though radical changes to borders can make this a less helpful technique. A standard Google image search for maps of the appropriate area or period can also offer examples of potential schemes, either from historic maps, contemporary depictions or the maps created by other people online. Grand strategy video games have been frequent sources for colour scheme options, and for simpler ideas- such as economic rankings or population density- even something as simple as the default colour options for excel can offer inspiration.
It would be remiss of me, however, not to mention the wide variety of colour schemes that have been created by various members of the online alternate history community- a number which has, indeed, been increasing at a seemingly exponential rate over the last few years. As a general rule older schemes in this category tend to be more limited in scope, but as a consequence easier to use, while later schemes offer a seemingly infinite variety of options that can be very useful for inspiration but can require you to be quite selective about what available colours to use to create a clear and comprehensible map.
Creating your own scheme
Being selective with options from an existing scheme is arguably the first step towards creating your own schemes. While some people will end up developing their own set of colours for all the maps they do, it's really only necessary to maintain colour continuity over a single project- such as all the maps to be included with a given timeline or set in the same universe. If you decide to start completely from scratch there are two avenues worth considering.
The first is to examine the reasons behind many existing schemes and how the changes depicted in your map might affect these. Both flags and military uniforms have been commonly used as the basis for colour schemes both in the online community and on traditional maps. though the frequency of some colours (particularly red white and blue in flags) among countries can make this of limited value.
One of the most well known is the tradition of referring to the British Empire as 'painting the world pink' due to the ubiquitous use of a pale red for depictions of British territories in the English-speaking world. This was actually a compromise between the traditional use of a bright red for Britain and the need for legibility (as well as a side effect of fading inks in some cases), later reinforced by the association of red with Communism. Naturally many depictions of a Communist Britain (with or without the Empire) use that self-same bright red to indicate the new political system, but a more visually arresting effect could, perhaps, be achieved through an assumption that red would be associated with the old regime and using a different colour- with green and purple among the most likely- for the new People's State.
Similarly the association with the Netherlands with the House of Orange has, naturally, led to the use of Orange to represent that state in most maps, both historical and online, and indeed in the German tradition as well as the English tradition. It's tempting to consider how a surviving heir of William III could lead to Orange instead being associated with Britain, or the potential colours that would be associated with the Netherlands if Staadtholderless Period continued unabated.
As a final example the German tradition has traditionally used blue for Prussia (originally a dark blue, closer to Prussian Blue in shade, but later switching to a lighter colour), green for Bavaria and Orange for the Habsburg domains. Yet blue and white are also the national colours of Bavaria, and in a world where it was Austria which united Germany instead of Prussia it's feasible that we'd instead see the Habsburgs depicted in gold, Bavaria in light blue and Prussia remaining a somewhat less legible dark blue.
The other avenue to consider is the balance of colours used. As a general rule, more intense colours will 'pop' and stand out more than more subdued shades, and the latter are to be preferred for a map due to this making any labels applied more legible. Similarly, unless a monochrome effect is desired, a broad spectrum of colours is likely to be more understandable than a narrow range of similar hues, though this should be tempered with the fact that too many colours can lead to a cluttered finish.
Colour Theory
It is at this point that I must introduce at least the basics of colour theory. To begin, consider the colour wheel below.
As you can see it depicts the standard primary colours- red blue and yellow- and secondary colours- Orange, green and Purple- along with a number of more intermediate tertiary colours. There are a number of standard arrangements of colours that can be drawn from this. The first are 'complimentary colours' - two colours from opposite sides of the colour wheel such as red and green, or blue and orange. Then there are analogous schemes which use neighbouring colours on the wheel, and tend to produce a more subtle effect that's easier on the eye than the contrast of complimentary colours. A three or four colour effect can be achieved by using colours at equal points along the wheel, though in a four-colour scheme a more aesthetic look can often be achieved by using two pairs of complementary colours.
The other consideration is the question of 'warm' vs 'cool' colours. Warm colours- red orange and yellow- tend to visually 'come forward' and be more prominent in an image while cool colours- blue, green and purple- will 'recede' and be less prominent. This is one of the reasons why using a pale blue for areas of water works as a good 'background' colour effect. Bear in mind however that an intense blue will still look more prominent than a soft red.
As a final note, the question of accessibility is one which is not likely to be one you need to worry about, but on occasion rears its head. While for the most part this expresses itself in the use of larger text and clearer fonts, the choice of colour is of importance as well. This is particularly noticeable with referendum maps where red/green colour blindness can make the most obvious scale illegible, which has led to increasing use of red/blue or blue/yellow in official literature.