Genuary.art JAN.27 challenge was to use these 5 colors, challenge accepted with fountain pen and actual ink. There are no such very light ink so I have simply dilued a Diamine Earl Grey ink with water. The other inks are Twilight, Imperial Purple, Amber and Hope Pink. (all from Diamine)
These zig zags are useful for testing inks and I may use this technique more in the future. The lines are compressed using x.powf(2.0) where x is in 0.0 -> 1.0 range which makes it more and more dense on the left side and allow to see how the ink is going to saturate.