Question: Which ink color (black or blue) is required for signing legal documents? Answer: Thanks a lot. I expected this question to require 5 minutes to research. An hour later, I am still reading… ...

The water carries some parts of the ink components further than others, and the colors separate out into a range of colors. Different brands use different combinations of ink to produce their black ...

Color Shifting Ink Perhaps the most ... The old green Treasury seal hidden behind the "100" has long been part of U.S currency and will remain an important security feature.