Here is a long establish manufacturer of ink. Since 1892 they have been producing ink. There are five generations of employees working in the company. The company makes a range of inks that include those for calligraphy, drawing, lithography and artists - so when looking at inks from this company you are considering the writing inks which are manufactured for fountain pens.
The company prides itself in using specially treated water, brilliant colourants and a minimum number of additives. Two of their inks are iron gall based. These have higher levels of acidity, and while iron gall inks can be used in fountain pens, make sure you empty and flush out the pen at least once a month. The acidity of the ink can corrode steel parts exposed to the ink. The iron gall ink colours will intensify as the ink oxidizes in the air.
The ink comes in a very basic glass 50 ml bottle with a metal screw on cap.
The 40 Series, inks for fountain pens, is available in:
2019 - 40-802 A a beautiful rich dark brown - Maroon.
2018 - 40-801 Aubergine, which looks just as it is titled, a beautiful rich purple eggplant.