Platinum Chou Kuro Black Bottled InkDescribed by Platinum as the darkest black ink in its 104 year history, water resistant Chou Kuro Black Ink was introduced in July 2023. Platinum's intensive testing of this new ink indicates that it is nearly fifty percent darker than the already popular Platinum Carbon Black ink. Platinum's inks have always been very safe to use with any fountain pen. However, as with any non traditionally formulated ink, we encourage customers to be cautious about