# File lib/color/cmyk.rb, line 137
137:   def to_grayscale
138:     c = 0.299 * @c.to_f
139:     m = 0.587 * @m.to_f
140:     y = 0.114 * @y.to_f
141:     g = 1.0 - [1.0, c + m + y + @k].min
142:     Color::GrayScale.from_fraction(g)
143:   end