Gel pens, or perhaps rather gel pens in Norwegian, are pens filled with pigmented gel instead of regular liquid ink. Gel pens are a relatively new invention – the first gel pen hit the market in Japan in 1984. If you want a pen that writes with strong color, choose a gel pen. The ink jelly used in gel pens is thicker than ink, which in turn produces a stronger color on paper. Gel pens often also tend to be more comfortable to write with than ballpoint pens, as the gel slides more easily over the paper.