title: Color Theory: How to convert Munsell HVC to RGB/HSB/HSL
body: <p>I'm looking at at document that describes the standard colors used in dentistry to describe the color of a tooth. They quote <em>hue</em>, <em>value</em>, <em>chroma</em> values, and indicate they are from the 1905 Munsell description of color:</p>
  
  <blockquote>
    <p>The system of colour notation
    developed by A. H. Munsell in 1905
    identifies colour in terms of three
    attributes: HUE, VALUE (Brightness)
    and CHROMA (saturation) [<a href="http://www.specialchem4coatings.com/tc/color/index.aspx?id=munsell" rel="noreferrer">15</a>]</p>
    
    <p>HUE (H): Munsell defined hue as the
    quality by which we distinguish one
    colour from another. He selected five
    principle colours: red, yellow, green,
    blue, and purple; and five
    intermediate colours: yellow-red,
    green-yellow, blue-green, purple-blue,
    and red-purple. These were placed
    around a colour circle at equal points
    and the colours in between these
    points are a mixture of the two, in
    favour of the nearer point/colour (see
    Fig 1.).</p>
    
    <p><img src="https://i.stack.imgur.com/XCZph.png" alt="alt text"></p>
    
    <p>VALUE (V): This notation indicates the
    lightness or darkness of a colour in
    relation to a neutral grey scale,
    which extends from absolute black
    (value symbol 0) to absolute white
    (value symbol 10). This is essentially
    how ‘bright’ the colour is.</p>
    
    <p>CHROMA (C): This indicates the degree
    of divergence of a given hue from a
    neutral grey of the same value. The
    scale of chroma extends from 0 for a
    neutral grey to 10, 12, 14 or farther,
    depending upon the strength
    (saturation) of the sample to be
    evaluated.</p>
    
    <p>There are various systems for
    categorising colour, the Vita system
    is most commonly used in Dentistry.
    This uses the letters A, B, C and D to
    notate the hue (colour) of the tooth.
    The chroma and value are both
    indicated by a value from 1 to 4. A1
    being lighter than A4, but A4 being
    more saturated than A1. If placed in
    order of value, i.e. brightness, the
    order from brightest to darkest would
    be:</p>
    
    <p>A1, B1, B2, A2, A3, D2, C1, B3, D3,
    D4, A3.5, B4, C2, A4, C3, C4</p>
    
    <p>The exact values of Hue, Value and
    Chroma for each of the shades is shown
    below (<a href="http://www.lib.umich.edu/dentlib/Dental_tables/Colorshadguid.html" rel="noreferrer">16</a>)</p>
    
    <p><img src="https://i.stack.imgur.com/8uVbD.png" alt="alt text"></p>
  </blockquote>
  
  <p>So my question is, can anyone convert Munsell HVC into RGB, HSB or HSL?</p>
  
  <pre><code>Hue    Value (Brightness) Chroma(Saturation)
  ===    ================== ==================
  4.5    7.80               1.7
  2.4    7.45               2.6
  1.3    7.40               2.9
  1.6    7.05               3.2
  1.6    6.70               3.1
  5.1    7.75               1.6
  4.3    7.50               2.2
  2.3    7.25               3.2
  2.4    7.00               3.2
  4.3    7.30               1.6
  2.8    6.90               2.3
  2.6    6.70               2.3
  1.6    6.30               2.9
  3.0    7.35               1.8
  1.8    7.10               2.3
  3.7    7.05               2.4
  </code></pre>
  
  <p>They say that Value(Brightness) varies from <code>0..10</code>, which is fine. So i take 7.05 to mean 70.5%. </p>
  
  <p>But what is <code>Hue</code> measured in? i'm used to <strong>hue</strong> being measured in <code>degrees</code> (0..360). But the values i see would all be red - when they should be more yellow, or brown.</p>
  
  <p>Finally, it says that Choma/Saturation can range from <code>0..10</code> ...or <em>even higher</em> - which makes it sound like an arbitrary scale.</p>
  
  <p>So can anyone convert Munsell HVC to HSB or HSL, or better yet, RGB?</p>