Hi Barbara. To help you in your search for the perfect blue, you may find this useful: https://youtu.be/UXLzYgYUtB0
I started following Mr. Jecks a number of years ago to get some inspiration from his authorship. Turns out he is also an aficionado of pens and inks. These are the Diamine inks, but he does Akkerman and one he is especially fond of; Akkerman Israel’s Zeeblauw. Enjoy the rabbit hole.