To examine this, tape a writing sample against a window with lots of sun exposure. Standard colors for ballpoint ink are black, blue, red and green. Plastic materials are usually printed with aniline inks, which contain methyl alcoholsynthetic resins, and shellac.
Ink is the traditional painting medium of China and Japan, where it has been used with long-haired brushes of wolf, goat,… Writing inks date from about bc and were used in ancient Egypt and China.
Especially Oyster Grey has a great shading. Furthermore, you should be advised to keep them away from liquids since they are not water-resistant. It was not until the beginning of the 20th century that ink-making became a complicated chemical-industrial process.
Pens with reservoirs were known since 10th century but were not widely used. Carbon inks were commonly made from lampblack or soot and a binding agent such as gum arabic or animal glue. Together with a broad nib, they make a great document marker. After standing it becomes darker and insoluble in water, which gives it a permanent quality.