The Hydrogen Limited Edition uses a combination of magenta ink and magenta metallic ink. The color magenta was chosen for the Limited Edition because of the color emitted by hydrogen gas when an electric current is passed through it. At low current levels hydrogen will emit a bluish lavender color, and at higher current levels it will turn a pink magenta color.
It should be noted that the metallic ink will be a shade darker than the rest of the magenta ink. This is to help ensure the two inks are distinguishable from one another.