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Please correct me if I am wrong, but from what I observe, you can easily get 100-150 colours in a set of pencils, but if you go for sets of watercolors, there's rarely more than 24-36.

Why so?

Joachim
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J. Doe
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2 Answers2

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The answer is quite simple really: you can mix watercolours (and paints in general), whereas you can't easily mix coloured pencils.

For example: If I have two different blues - a light and a dark - and I want a blue that's halfway in between, with watercolours I can just take roughly equal quantities of each, mix them together and use that.

With pencils, I would have to apply both, and try and get the shading just right so that you end up with a medium blue rather than an uneven mess. Because this is more difficult, people prefer to have a wider range of colours, and so because there's a market for it, manufacturers sell this wider range.

walrus
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    Indeed, if watercolors were to mix perfectly, then you would only need three. – Jörg W Mittag Aug 20 '18 at 09:38
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    @JörgWMittag convenience is the key word here. – JAD Aug 20 '18 at 09:39
  • @JörgWMittag only if the watercolors were perfit primary colour and I expect that is not possible. – Ian Ringrose Aug 20 '18 at 13:20
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    @IanRingrose No 3 points in the human gamut can cover it; the human colour gamut is horseshoe shaped, not a triangle. There are many other issues too. – Yakk Aug 20 '18 at 19:34
  • @Yakk Can't yellow cyan magenta watercolours and water work together to create the range? Assuming that the paper is white and the watercolours have the potential to be opaque. – wizzwizz4 Aug 21 '18 at 04:34
  • @wizzwizz4 no, because the CMYK colourspace is additive, not subtractive - if you shine cyan, magenta and yellow light you get white, not black. RGB is subtractive, which is why it works for paints and things that absorb light. – walrus Aug 21 '18 at 08:23
  • @walrus You mixed them up. Think: which one do printers use, and which do computer screens use? – wizzwizz4 Aug 21 '18 at 09:51
  • @wizzwizz4 ah yes, apologies. This wikipedia article does suggest that it would be possible, since that's how printer inks work. – walrus Aug 21 '18 at 09:54
  • @wizz gamut problems. https://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/CIExy1931_srgb_gamut.png/240px-CIExy1931_srgb_gamut.png -- no single triangle can cover the entire horseshoe shaped colour (hue/sat) space of human perception. And practical issues make the extreme parts hard to reach using pigments, let alone water soluble ones. – Yakk Aug 21 '18 at 13:16
  • @JörgWMittag For watercolor in particular, you might also want some variation in granulating vs non-granulating...or other properties. – user3067860 Aug 21 '18 at 13:55
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Something else that may help to explain the difference is that watercolor painters can be quite picky about which paints they choose for mixing. Each watercolor paint is made from 1 or more pigments, which are some sort of substance that is used to make the color. For example, the color winsor yellow deep contains one pigment: PY65. In contrast, cadmium yellow contains two pigments: PY35 and PO20. Since watercolor is translucent, mixing colors can be a delicate process, and the more pigments that are mixed into a single color (regardless of how many different tubes of paint are used), the muddier the color gets. So, if you're buying a good quality watercolor paint set, it is likely to include mostly single-pigment colors and few pre-mixed (two-pigment, three-pigment, etc.), since single-pigment paints can be mixed more easily before becoming muddy. If the paint set included 100 different colors of paint, many of those colors would already contain three or four pigments, and would not mix or blend well with other colors.

(You can find more information about watercolor paints at pigments at https://www.handprint.com/HP/WCL/palette1.html)

EmKayDee
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    Welcome to Crafts.SE, EmKayDee. This is a great answer. – walrus Aug 20 '18 at 16:01
  • EmKayDee's answer is excellent. I would only add that producing the color you want with watercolors is easier than with colored pencils, as noted, but is dependent on the spectrum of the pigment(s) in the watercolor, even when there is only one pigment. The best book IMHO ever written on how to attain particular hues with various water-borne pigments is Wilcox's "Blue and Yellow Don't Make Green". https://michaelwilcoxschoolofcolour.com/product/blue-and-yellow-dont-make-green/ – N.A.Neff Jan 11 '23 at 18:33