Heimdall is the god of light in Norse mythology. Heimdall Ink is an ink that transitions naturally from a bright yellow color, like the sun, to orange, and when applied generously, it can even display a reddish hue. This ink has a wide color range.
One can use Wearingeul Glistening inks with fountain pens, but only for F/M/B nibs, Not for EF nib. Even with bold and thick nibs, one needs to give special care to the fountain pen and has to clear and clean the feed often.