In formal occasions, contract documents will be signed with black ink pens and signature pens, because black ink pens and signature pens mainly contain carbon, which is well known to those who have studied chemistry and is not easy to be oxidized. The main component is carbon black (soot), which is elemental carbon. Its chemical properties are stable, black and shiny, and it is suitable for long-term preservation of writing materials. Nowadays, ink pens are used less. The widely used signature pens are divided into oil pens, gel pens and ink pens.

For example, we also use black ink pens in exams. This is because when scanning the test paper, there will be light hitting the paper. If we use other colors, the handwriting will become unclear or even intermittent for some optical reasons, and it is difficult to explain it clearly in one or two sentences. So it's not that the blue one will be invisible, but the words written by the blue pen will be illegible. Most importantly, some colors will be ignored by the machine. It is recommended that you use black pens according to regulations.

Generally speaking, black pen or carbon ink pen is used to sign important documents. The reason should be that black ink can be used for a long time. If there is an accident, such as the document is wet by water, the black handwriting is still very clear, but nothing else works, so everyone signs the document with black pen. ?

Then, if you need to copy some contract agreements, etc. Black ink pen will be clearer and easier to read than other colors and will be much inferior. At the same time, black will have a high degree of recognition, giving people a solemn and sacred feeling. Other colors can make people feel dazzling, confusing and visually conflicting.