1994

\(\begin{align} &\Delta E = \sqrt{ \left(\dfrac{\Delta L}{K_LS_L}\right)^2+ \left(\dfrac{\Delta C}{K_CS_C}\right)^2+ \left(\dfrac{\Delta H}{K_HS_H}\right)^2}\\ &\Delta L = L_1-L_2\\ &\Delta C = C_1-C_2\\ &\Delta H = \sqrt{\Delta a^2+\Delta b^2-\Delta C^2}\\ &C_1 = \sqrt{a_1^2+b_1^2}\\ &C_2 = \sqrt{a_2^2+b_2^2}\\ &\Delta a = a_1-a_2\\ &\Delta b = b_1-b_2\\ &S_L = 1\\ &S_C = 1+K_1C_1\\ &S_H = 1+K_2C_1\\ &K_L = \begin{cases} 1&\text{default}\\ 2&\text{textiles} \end{cases}\\ &K_C = 1\text{ default}\\ &K_H = 1\text{ default}\\ &K_1 = \begin{cases} 0.045&\text{graphic arts}\\ 0.048&\text{textiles} \end{cases}\\ &K_2 = \begin{cases} 0.015&\text{graphic arts}\\ 0.014&\text{textiles} \end{cases} \end{align}\)