Yes, anything that gets you painting is good, and I felt the same about these courses. I'm pointing out my reservations about a couple of things (well, the choice of two colours, really), but otherwise I'm all for it. As for lightfastness, it is true that anything I do right now is not good in my eyes, but then it is no more expensive or difficult to use lightfast pigments as fugitive ones, and if my great grandparents, say, had painted, and I had been passed down a copy, I would have been really pleased. So why not?
OK, I was going to say something about his recommended palette (i.e. his choice of colours, as against the pigments used to make those colours). First, let me say there is nothing at all wrong with it, as every palette is a compromise, so you make a compromise that suits you. Understanding the choices can help you work out what you would like to change–if anything.
First, gamut, which is just a word to describe the total set of colours you can mix with a given set of paints. This is a limited gamut set, which you may or may not like (Trevor Chamberlain uses a fairly limited palette and I love his work). Everyone is familiar with the colour wheel, yes? With the colours around the outside, usually yellow at the top, going through orange, red, purple, blue, cyan, blue-green, and yellow-green. So the angle determines the colour (called the hue angle). The middle of the wheel is neutral grey or black (or white, there are actually three dimensions, the third being value), so the closer to the middle you get, the less colour and more neutral it is. take two of the paints, let's say ultramarine and alizarin crimson, and make a number of mixtures, starting with pure blue, then with a little of the red added, more and more red, till in the final pile there is pure alizarin. If you found ultramarine and alizarin on the colour wheel and drew a line between them, you have basically mixed all the colours along that line (I'm simplifying slightly, the line may not be perfectly linear, but never mind).
Now take a third colour, say yellow ochre, and mix some of that in with any of the piles you have made, and you can see that you can pull the colour made anywhere along the line towards the third colour. In fact, if you find all three colours on the colour wheel, and join them with a triangle, the interior of that triangle is the full range of colours you can mix with those three paints, ok? But yellow ochre isn't a very bright (saturated, or chromatic) yellow, and alizarin crimson is a fairly dull red. There is no possible way to make a brighter yellow than yellow ochre by adding blue or red to it, yes? Similarly, you can't make a brighter orange by mixing yellow ochre and alizarin than what is on the line between the two on the colour wheel, but cadmium orange, say is much more orange than that. The fact that a line between any two points on the colour wheel goes closer to the middle at all points between them is called saturation cost. It means that if you choose colours that are spaced far apart on the colour wheel, you can only make fairly dull (low chroma) mixes with it. If you mixed, say, lemon yellow and perinone orange, you can make very bright orangey yellows and oranges, because they are close together. And for any pure paint you have, you can't make anything more chromatic than the pure paint itself. So, to get the widest gamut, you need very saturated paint colours that are not too far apart. Makes sense, yes?
Looking at this palette choice, you can see that aureolin, yellow ochre and burnt sienna don't expand the gamut at all, they are convenient for mixing dull browns and yellows, but you could do that with the other colours. You can only make pretty dull greens, because ultramarine and lemon yellow are a long way apart, and dull purples, because you only have a dull red to begin with.
Six watercolours (plus white gouache), but you can get a much more extensive gamut by choosing six saturated (chromatic) colours evenly spaced around the spectrum. also, the subtractive primaries are not red, blue and yellow, as they thought in the 18C, but cyan, magenta, and yellow, so we'll include those, and colours equally spaced between them.
Lemon yellow (windsor lemon PY154)
Cadmium scarlet (PR108)
Quinacridone magenta (PR122 w&n is good here)
Ultramarine blue (PB29)
Phthalocyanine blue Green Shade (PB15:3, e.g. W&N winsor blue gs)
Phthalocyanine green Yellow Shade (PG36)
These are all lightfast, and pthalo blue G/S and cadmium scarlet give very deep blacks Cadmium scarlet and quinacridone magenta give a full range of reds.
I mention W&N as they are very commonly available and good. The best watercolour brands are Daniel Smith, W&N, MaimeriBlu and M. Graham.
I would extend that a little with a couple of convenience dull colours in the warm part of the spectrum,
Nickel dioxine yellow (PY153) or yellow ochre
Quinacridone burnt orange (PO48) or Burnt sienna
Perylene maroon (PR179). (good alizarin crimson replacement)
So eight or nine colours, all the convenience of the original, more mixing complements, much greater gamut, and all lightfast.
