The ‘Cool and Refined’ set consists of Green, Dark Blue, Violet ... Buy now £10.50, Cult Pens STAEDTLER 264-1 Textsurfer Gel Ultra-Soft Highlighter, 3mm Line Width - Yellow (Pack of 10 ...

To understand how this works in highlighter pens, we can compare them to ordinary ballpoint pens. When light hits the ink of a blue pen, the ink reflects blue light and absorbs other colours ...