𝜟𝜱✴ = contrastDPS(color1, color2);
If you've implemented the code and want a quick sanity check, Here are some keystone checks with no rounding. The first color is TEXT and the second color is BACKGROUND:
Test Values for 0.0.1 constants.
#000 & #9e9e9e ∆Φ✴: 52.042324818974436
#9e9e9e & #FFF ∆Φ✴: 52.15817941439123
#FFF & #888 ∆Φ✴: 63.155229570915864
#888 & #000 ∆Φ✴: 40.15402173709839
#000 & #aaa ∆Φ✴: 58.397040139078555
#aaa & #234 ∆Φ✴: 49.71988060967246
#234 & #def ∆Φ✴: 84.77424837874361
#def & #123 ∆Φ✴: 88.70761679910729
#123 & #444 ∆Φ✴: 0.0
#444 & #777 ∆Φ✴: 11.029421871598664
#777 & #a4a4a4 ∆Φ✴: 12.543444585172274
#a4a4a4 & #fff ∆Φ✴: 48.902933046054386
#fff & #000 ∆Φ✴: 101.35051965850337
#000 & #595959 ∆Φ✴: 13.468722550811329
Some APCA Lc values for comparison:
#888 vs #fff APCA Lc 63.056469930209424
∆Φ✴: 63.155229570915864
#000 vs #aaa APCA Lc 58.146262578561334
∆Φ✴: 58.397040139078555
#123 vs #def APCA Lc 91.66830811481631
∆Φ✴: 88.70761679910729
#123 vs #444 APCA Lc 8.32326136957393
∆Φ✴: 0.0