SuHo紙保存

Understanding acid-free paper
Besides documentations, books, blueprints, maps, and posters, paper relics come in many other different forms.

Even art creations, such as Chinese traditional calligraphy, drawing, Western sketch, porcelain, watercolour, and block print, are also forms of cultural relics.

In addition to the basic material-paper, we may also find paint, ink, and other substances applied in the aforementioned relics. For better preservation of these valuable documentation and art creations, we use covers, stiches, and glue are used for binding books; while silk, paste, wood, and bamboo are used for framing art works.

Fiber is the basic component of paper relics.
Theoretically speaking, fiber itself is not subject to any outside factors. However, paper (including paper relics) is susceptible to physical, chemical and biological changes, which makes the preservation of paper relics difficult.

Thorough preservation of paper collections is usually disregarded until problems arouse.
However, this is not the ideal method.
Prevention is always better than cure.
Through analyzing the intrinsic and extrinsic factors, we can unveil the secrets why these ancient paper relics can last for thousands of years.

Predecessors used to make paper with natural materials and lime. Lime contributes to the alkalinity of paper. Even after counteractions with the acids in air, this kind of paper remains alkaline, hence is resistant to damages and deterioration.
Shang paper and acid-free paper are examples of this higher quality paper.

Even with the intrinsic advantages, proper maintenance is still the extrinsic factor required for the preservation of the longevity of paper.
Our predecessors came up with brilliant methods as follow for better paper preservation:

Since air is crucial to paper relics, woods that provide higher ventilation, such as fir woods and parasol trees, are excellent choices for storing and framing materials.
These woods are dryer and less prone to oil oozing or color fading.
In addition, these woods can modulate the temperature and humidity inside and outside the boxes or frames, hence eliminate the possibility of excessive damages or decay caused by frequent exposure to air.

Some of the paper relics came in enormous sizes,therefore, it was difficult to fit them inside wooden boxes for preservation.
Once the paper was exposed to sunlight, it was prone to color fading. So they thought of covering the paper relics in black cloth to absorb heat and prevent exposure to the outside environment.
History proved this to be a good method for paper preservation.

Bookworm is the natural enemy of paper.They enjoy gnawing colloid or starch of paper. Therefore, if the paper is left unprotected, it is prone to be another feast for bookworms. To prevent this from happening, our predecessors thought of the following methods:
1.Dying The "yellow paper", dyed with a pesticide made from the philodendron solution, excelled in keeping bookworms away. In addition, some people of the time soaked paper in a solution made from wild pepper. Its intensely "spicy-hot" odor repeled the pests.
2.Scents Ancient people used substances with a strong odor to repel pests. By placing musk, papaya, rue, camphor and realgar in wooden boxes or shelves they kept the bookworms away.
3.Pest-repellent paper People in the past used to add a special piece of leaded paper in the title page, the cover, and the back of the book respectively. Once the bookworms ate it, they died. Hence this special piece of paper is called pest-repellent paper. Furthermore, lead is stable in air. After thousands of years, it is still able to maintain the original bright red colour and is still able to prevent paper from worms. Thus comes the name "Ever Red" for lead.
4.Paper with less rosin and starch Certain substances such as rosin, pectin and starch may accelerate the deterioration of paper. This is because the acidity in rosin will erode the fiber and pectin and starch which attracts bookworms. Therefore, the less rosin, pectin or starch contained in the paper fiber, the better the paper will survive deterioration or erosion. Rosin-free paper with less pectin in its fiber, such as hemp paper or mulberry-bark paper, are the best alternatives for preservation purpose.
5. Keeping dry Bookworms love moisture. Dry conditions could be unfavorable or even fatal to their living. In the past, people used to dry paper in dusk in certain seasons (e.g. autumn). The high temperature of the ground surface kills worm eggs and forced the worms to move out .However, paper should not be exposed directly to sunlight for fear of possible damages to the paper.

Next, a further examination into "acid-free paper" which will explain why it is a tremendous help/breakthrough in the preservation and restoration of paper relics.