Thank you! I add it right now!

Thank you, now it seems obvious indeed !

I have added a suggestion to add an example to make it a bit clearer if some other people also have trouble understanding this.

I think the link between color codes and units of ink needed would be a bit clearer with one more example. I suggest something like:

A pixel with the color code 'fefdfc' need 1 unit of Red, 2 units of Green and 3 units of Blue.
A pixel with the color code '00ff01' need 255 units of Red, 0 units of Green and 254 units of Blue.

It's in hexa. FF means 255 it's the max, FE means 254 its FF minus 1.

I am having trouble understanding the link between the color codes and the units of ink used. Could you help me with that ?

good job! I like your code, everything is laid out on the shelves.