The handwriting must be long and shallow, and then slowly disappear. But if you don't wipe it, it will last longer. If the pencil is written on paper, there is no eraser, and there is no artificial smearing and blurring caused by the friction of double-page handwriting (the so-called ideal situation), it will last longer.
For example, in college, in order to copy neatly, my notes on advanced mathematics (Volume II), linear algebra, complex variable function, college physics and other subjects all used mechanical pencil notes. Six years later ... the phenomenon of double-page handwriting rubbing is serious. If it is not remedied, it will probably be completely blurred after n years. Therefore, some time ago, Spray Fixative was adopted to protect cultural relics, and the whole area was reduced to 20 oceans.
Without Spray Fixative and Spray Fixative, pencil handwriting can be preserved for more than ten years ~ ~
Looking through the homework more than ten years ago, the pencil is light in color, but the handwriting is still very clear.
The main reason why the pencil handwriting is blurred is that after the notebook is closed, the handwriting on both sides of the paper rubs against each other, which makes the handwriting blurred. However, under ideal conditions, pencil handwriting can still be preserved for a long time. For example, it is found that there are medieval pencils, which are more stable than ink and ink as long as they are not rubbed. Drawing charts on ocean-going ships (that is, drawing lines on the charts to determine the course) is internationally stipulated to use 4B pencils for two reasons. First, charts are expensive and need to be reused, and pencil words are easy to erase and modify. Secondly, pencil handwriting is insoluble in water, and seawater can do nothing about it. Chart is one of the important nautical records. In case of shipwreck and sinking, the pencil handwriting on the chart is still legible. Before the ship sets sail, it is the second mate's job to draw the course on the chart with 4B pencils (the second mate reports it to the captain for review), so after the ship arrives at the port, the second mate often buys a large bundle of wooden 4B pencils. In the cab of some ocean-going ships, a copper electric pencil sharpener is fixed on the side of the table. Just insert the wooden pencil and take it out at once, and the pencil will be sharpened. It will be valuable to collect a bulky copper electric pencil sharpener. (2) Any ink in the brush has a fading period, but the calligraphy and painting written by the brush has been intact for thousands of years.
As long as the pen is not in fashion, it will be fine for hundreds of years. For example, the manuscripts of great European writers waving great musicians are all written with pens (quill pens). 4 Water-based pens fade in water (loose color), while gel pens are slightly better. In view of the short use time of water-based pen, it is similar to a pen in theory. Ballpoint pen is theoretically longer than pen, which is related to the difference of ink, and it is better than pen after soaking. But the ballpoint pen has not been used for decades, so the oldest handwriting of ballpoint pen is limited to recent decades. For example, the outline of local armed forces in western Fujian (there are several red ballpoint pens. ) I can't think of other kinds of pens at the moment. If you have any questions, you can ask.