CCL = [27.07510258707097, 34.38502265503816, 42.02402843768756, 49.50112987272844, 57.173277387157796, 65.74123652910247, 74.82268281895817, 83.32566595929231]
        l1, a1, b1 = grf.to_spectra(*self.c1).to('lab').values
        l2, a2, b2 = grf.to_spectra(*self.c2).to('lab').values
        lscale = (l2 - l1) / (CCL[-1] - CCL[0])
        palette = []
        mcol = lambda x:  max(min(int(x * 255. + .5), 255), 0)
        for i in range(8):
            f = i / 7.
            c = spectra.lab(
                l1 + (CCL[i] - CCL[0]) * lscale,
                a2 * f + a1 * (1 - f),
                b2 * f + b1 * (1 - f),
            )
            r, g, b = c.to('rgb').values
            rgb = (mcol(r), mcol(g), mcol(b))
            palette.append(rgb)