n">cHK</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span> <span class="c1"># last term is contribution of Helmholtz-Kohlrausch effect on brightness</span>

            <span class="c1"># calculate saturation, s:</span>
            <span class="n">s</span> <span class="o">=</span> <span class="n">M</span> <span class="o">/</span> <span class="n">Q</span>
            <span class="n">S</span> <span class="o">=</span> <span class="n">s</span> <span class="c1"># make extra variable,