Everybody who paints watercolour, hobbyist or professional, has a unique palette. As paints and pastels are my vice, I have a large collection of paints I will probably never be able to use up during my lifetime(especially because I paint smaller than most people). That doesn't make me any less aware that I will probably end up unbearably encumbered if I wanted to carry a palette of 100 different paints on a six-kilometre hike. Naturally, I end up choosing different paints for different paintings. The decision is usually made impulsively. When I am going travelling for a week, however, it's not a choice I could afford to regret any time later.
That made me purchase a small 18-well palette from a local art supply store and actually think for a while before pouring paints into it.
What would I need? I would be painting with a medium-to-small waterbrush and dried tube paints, and would mostly be painting either landscape or still life. I would probably not meet an attractive human I would want to paint, and as much as I love to paint birds, I know that I cannot hold a pair of binoculars, a sketchbook and a brush at the same time. That was quite easy to figure out. I would also probably not want to spend too much time worrying about mixes; I would prefer to be able to achieve a large range of hues without mixing any more than two colours. I actually much prefer not having to mix colours at all. Those were the factors I needed to take into account: a hue range for landscapes and still life and a relatively small need for mixing.
Then I examined my stash of paints, and poured out those 18 colours.
Probably the yellows and the reds would be quite intuitive; almost everyone has a lemon yellow and a "middle" yellow, an orange-red and a red. The split primary palette results in drab unsaturated mixes, so I did not bother to include a "cold", crimson-red. Instead I included a magenta and a magenta-violet; one can mix crimson from magenta but never magenta from crimson.
With a magenta, blue and cyan, violets are probably unnecessary in an extremely limited palette. I included them anyway and I included two of them, not because I needed them but because PV15 and PV16 are interesting paints in a wash. With most of my palette being organic, non-granulating pigments, some mineral pigments were quite helpful in achieving textural effects.
Now the blues - blue paints are my absolute favourite. Ultramarine is a staple for many painters and relatively consistent across manufacturers. I picked two different phthalo blues because I personally find PB17 more attractive than the somewhat stronger, less green PB 15:3. As for the cerulean, I wanted both the granulation and the relatively pastel quality of the paint for skies and water bodies.
The choice of greens and earths are perhaps somewhat more idiosyncratic than that of others. Some kind of a phthalo green was an absolute necessity to mix bright spring greens; I could have chosen PG7, but it was not a very useful colour by itself; the W&N Aqua Green could be used as a tint by itself, which was a factor I wanted to consider. As for Green Apatite Genuine, it both makes a good single pigment substitute for sap green by itself and granulates wonderfully without looking contrived or unnatural; the paint made painting foliage much simpler ever since I discovered it. I chose Rare Green Earth for a similar reason; potential uses in landscape painting without mixing and granulating effects.
Burnt French Ochre and Quin Orange are rather similar in hue and are both much too bright to be substitutes for traditional earth pigments, and I selected them mostly because I thought they would mix nicely with either Green Apatite or Cerulean to yield convincing dark brown colours; I do not have a large collection of dull earths.
As for the Chromium Black, I simply do not like mixing my own blacks very much and thus wanted a black that could harmonise well enough without standing out too much.
