The CMYK value for 100% pure black ink is C=0%, M=0%, Y=0%, and K=100%. 100% black K, is different than HEX pure black value of #000000. 100% K black is true, everyday printable ink, and because of this it cannot truly absorb all light to create true black. When it's printed, the surface may have textures which reflect some part of light, making the surface's color off-black. The HEX equivalent to 100% black is #231F20 and the RBG value is R=35, G=31, B=32.