Table 1: Subjective assessment metric based on CIEDE2000 Color difference.

𝑘 Δ 𝐸 m i n ( 𝑘 ) Δ 𝐸 m a x ( 𝑘 ) Perception of color difference 𝑄

10.0 0.5Hardly 5
20.51.5Slight 5 ( Δ 𝐸 0 . 5 )
31.53.0Noticeable 4 ( Δ 𝐸 1 . 5 ) / 1 . 5
43.06.0Appreciable 3 ( Δ 𝐸 3 ) / 3
56.012.0Much 2 ( Δ 𝐸 6 ) / 6
612.024.0Very much 1 ( Δ 𝐸 1 2 ) / 1 2
724.0 Strongly 0