By Alex Richards
Having mastered the art of tracing, the next stage in creating a map is the addition of colour. While the actual mechanism of adding colour to a map is among the easiest techniques to learn, choosing which colours to actually use is perhaps the most commonly asked question in the field of alternate history cartography. The answer, as with everything, is highly dependent on the desired effect.
When considering colour, the first thing to remember is that it can be applied to two aspects of your map. Most obviously is the 'fill'- what can be considered as essentially colouring in the shapes you've drawn so far- but the application of colour to the lines themselves can be just as important for highlighting roads and rivers, or depicting more specialist information.
In raster programmes, colouring the 'fill' areas is simply a case of utilising the relevant tool, usually symbolised with a paint bucket. Here aliased images can pose some issues as the smooth finish can produce a 'halo' effect where the applied colour doesn't extend fully to the limits of the shape. However, in programmes such as Paint.NET, adjusting the 'hardness' setting to between 25% and 50% will expand the filled selection to account for this, albeit at the cost of removing the smoothness of the line. This can, however, be mitigated by producing a copy of the 'line' layer to apply this technique to, and is not an issue with anti-aliased lines. The same problem rears its head when trying to colour lines in raster programmes, which means that if aliased lines are desired, any tracing should be carried out using the colour desired in the finished map.
For vector programmes, the 'smoothness' issue is absent, and both fill colour and line colour can be changed using the 'fill and stroke' window. This can also be used to add patterns, such as stripes or dots, which is particularly useful when working in monochrome as it opens up new options. However, the process of altering the style or colour of these patterns from the default settings is frequently complicated and unintuitive, with that for inkscape in particular involving navigation of submenus in the effects menu and knowledge of hex-codes.
What to colour
The decision on what should, or indeed should not, be coloured in your map comes back to the principles of map-making I outlined in the first article of these series- the question of whether the map is to inform, illustrate or serve as decoration, and the format it will then use. As a general rule, the more a map is meant as a tool for information, the smaller the range of colours used should be, and the more willing you should be to leave areas of the map uncoloured if they are not relevant to the overall message of the map. Similarly careful use of labels can compliment a limited palette allowing the matching of colours to categories rather than requiring separate colours for each individual entry. The flip side of this is that a range of shades within a single colour can be a very effective and attractive style when you have a smaller number of categories to indicate.
At the other end of the scale from the informative map, the temptation with a decorative map is to use as many individual colours as possible- for example giving every country on the map its own colour. While this can work, it's worth remembering that many professional poster-maps follow some variation on the 'four colour rule' where only 4, 5 or occasionally 6 colours are used to colour in every country, state or other such division on the map. Not only is this potentially easier on the eyes than several hundred colours being placed next to eachother, but it's also a more printer-safe format to use. Going even further in simplification, a very effective cyberpunk or '80s CRT screen' style effect can be created by eschewing fill colours entirely and just treating your map as a wire frame in which all the borders and coastlines are coloured in a bright neon colour- usually green, yellow or white- against a black background.
If there's one principle of colour design to remember however, it's that if your map is going to appear entirely, or mostly, in a monochrome format (which most published works, either on paper or as ebooks, will be), it should be designed from the start in monochrome. This is due to the effects than anyone who's tried photocopying an image will be familiar with, where very different colours can become indistinguishable when converted to greyscale, darker colours can obscure writing, and lighter colours can disappear entirely. There really is nothing worse than spending a long time carefully creating an illustrative map, only to find it becomes illegible in the finished product. To assist with this, you should never feel concerned with changing the text colour to expand your possible range of options, though if you do decide to incorporate white text on dark colours its worth remembering that a larger font, one in bold, or one with thicker strokes, should be chosen as thinner lines tend to blur or misprint more easily with this combination.
Far more contentious than the question of what to colour, however, is the question of which colours to use, an area where aesthetics truly clashes with the desire for information. It is to this difficult subject that I shall turn in the next article.