Ink and paper activities

Inks were originally made from the natural pigments in living materials such as berries, nuts, and leaves. The pigments in a green leaf, for example, absorb all the color wavelengths of light except for green.

Therefore the green color is the only one reflected back to our eyes and the only color we see. (Remember ROY G BIV? A beam of light contains the colors of the rainbow: red, orange, yellow, green, blue, indigo, and violet.

Under normal circumstances, though, we don't see all of those colors because some or all of them are absorbed by the material they shine on.) Through chemical processes, these pigments can be extracted and turned into dye or ink. Here are some easy recipes for ink you can make at home.

Berry Ink. Use 1/2 cup fresh berries or thawed frozen berries; push them through a strainer so that you get pulp-free juice. Add 1/2 teaspoon of vinegar (to hold color) and 1/2 teaspoon salt (as a preservative) and mix well. You can use a glass baby food jar as your 'inkwell', if you have one.

Walnut Ink. Crush the shells of 12 walnuts by putting them in a sock and hammering them lightly. Pour the shells into a saucepan and cover them with water, then let them simmer for 30 minutes. After that, remove them from heat and let them soak overnight. Strain the shells out of the ink and add 1/4 teaspoon of vinegar to help preserve the color.

Invisible Ink. Try writing with lemon juice on a piece of paper using a paintbrush or Q-Tip. When the ink has dried, hold the paper over a toaster to heat it. Your writing should appear in brown lettering as the parts of the paper with acid from the lemon juice brown faster than the other parts. You can also make invisible ink from equal parts baking soda and water.

Brush grape juice over your secret message to reveal the writing—the acidic grape juice reacts with the baking soda, which is a base. (Find out more with our acids and bases experiments.)

Paper: In Egypt, the first paper was made from the water grass papyrus. In medieval Europe, calfskin was used to make vellum and the under-lining of sheep skin was used for parchment, on which scribes recorded financial transactions and monks copied scripture. But paper as we know it was invented by the Chinese by 105 AD—they used hemp pulp to form sheets of it.

The papermaking process was refined by the Arabs and arrived in Europe by the 1100s. Now we have technology that allows us to make shiny book covers and photo paper, fine-grained printer paper, and cheap newsprint. Better paper-making technology allows us to have access to paper in all sizes, shapes, colors, and textures. You can even make your own recycled paper!