For brush, pen, airbrush, calligraphy pen, techincal pen and fountain pens (some may require cleaning after use). Remix the exact same colour over and over again with the dropper system, 25 to 50% more brilliance than tube watercolour. Concentrated transparent colours that are intermixable and AP approved non-toxic.
Art Supplies from Jackson's | Watercolour Ink: Sets & Bottles : Dr Ph. Martin's and £5 - £10 | Jackson's Art Supplies - Jackson's Art Supplies - Finest Art Materials - Best Prices https://www.jacksonsart.com/en-ca/colour/watercolour/watercolour-ink?manufacturer=14017&pricebuckets=27167