Learn how ink can be made from natural ingredients. Gather roots and bark (for brown), berries (for red or purple), grass clippings and moss (for green), onion skins (for yellow) and chopped red cabbage (for blue). Place each material in a separate glass bowl, add enough water to cover, and microwave for 3 to 8 minutes until you achieve the desired color. Cool completely. Use the inks as watercolors or to write a letter with a feather (or a toothpick) as a pen. Be sure to protect your clothes and work surfaces to avoid permanent stains.