You must use uncoated card stock, cardboard, or other heavy, porous paper to get the best results with this pen.
After you write, the ink separates to create a silver metallic inside outlined with a black, blue, green, pink or violet line (depending on what colour pen you are using) on the outside. Interestingly enough, if you color in a larger area such as a square, the outline will always move to the perimeter of the object. Thus the inside of the square will be silver metallic but the outline of the square will have a colored line. Quite interesting ink technology!
These fiber tip pens are great for embellishing card stock, cardboard, notebook covers and more. Great for journal making and scrap booking!