Ink typing is a method used in analyzing questioned documents. It utilizes blotting paper, samples of ink, and samples from a document where the ink used is unknown. Each company has a patent for a specific color ratio in their black ink. This can help to identify the specific brand of pen used when writing. The reason black ink changes colors when blot tested is because it contains each color in the rainbow. Pen 2 is a good example of this. This was done in my Forensic Science class. I don’t remember the details of the first two pens but the third was a gel pen. Also, to those confused about the color thing— Black is absence of light reflection not color. It absorbs every color of light. White light contains every color of light. Black contains every color of pigment. The reason a healthy leaf looks green is because it absorbs every color of light but reflects green light.