Euclidean metric ignores "blue" channel?

[krlmlr]

I don't know much about colors, black == blue (in Euclidean space) strikes me odd. Is this expected?

farver::compare_colour(farver::decode_colour("#000000"), farver::decode_colour("#0000FF"), "rgb")
#>      [,1]
#> [1,]    0
farver::compare_colour(farver::decode_colour("#000000"), farver::decode_colour("#0000FF"), "rgb", method = "cmc")
#>         [,1]
#> [1,] 212.096

^{Created on 2020-01-11 by the reprex package (v0.3.0)}