photo by: Bill Jeffries  

book care


When beginning or maintaining a book collection, it is essential that you become familiar with the information that will help protect and preserve your library investment for generations to come. Books are far more fragile than most people realize and now with technology it’s possible to print books online and have them at home, so taking care of them is essential. Unlike art, porcelain, or furniture, the materials used in bookmaking and binding are more expendable. The pages themselves can tear, mildew, and even rot. The hemp cord and threads, along with the glues and adhesives used in bookmaking are prime targets for rodents and insects. A poor climate condition is one of the main causes of book damage and leather disintegration. The number one killer of books is the improper handling of them. It is important to educate yourself with a few simple things that can be done to prevent damage and preserve your collection.

The leading causes of book damage: 

poor climate and atmospheric conditions including excessive heat, moisture, and light, improper book handling, and insect damage.



Poor environmental conditions are a leading contributor to book damage. Extreme heat, moisture, or light will cause rapid deterioration of the book’s natural materials. Heat, when excessive, can cause your books to crack, flake, or become brittle. Never allow books to be in the direct flow of any heating ducts. The constant flow of hot air will dry out your bindings resulting in brittle and cracked leather. Avoid displaying books near windows, radiators, and fireplaces as well. A damp environment will cause paper to cockle and encourage chemical activity potentially resulting in mold, mildew, or pest damage. Very dry conditions are problematic as well; without enough moisture, the book’s natural materials can become brittle leading to pages that will become weak and easily torn. When the bindings themselves become dried out, they start to crumble and split. Either extreme heat or moisture will lead to rapid deterioration of the book’s paper. Stable conditions created through the proper levels of temperature and atmospheric moisture are essential in preserving the integrity of the books materials. The perfect condition for books and leather bindings is when the environment’s relative humidity is about 50%, and the temperature is between 66 and 72 degrees. Excessive humidity begets moisture, and moisture begets mold and mildew causing foxing, or the browning and blackening of pages. The appearance of brown or reddish spots is the first indication of mold and mildew damage. Often you can detect a musty odor as well. Books displayed in areas of too much moisture can be protected by investing in a good dehumidifier which will control most moisture problems. In addition, during the winter months, duct work systems containing a humidifier can also pump too much moisture into the air further leading to book damage. Once again, a dehumidifier will control these potential atmospheric problems. Humidity is the weight or mass of water vapor in a certain volume of air. Never allow the relative humidity to exceed 70%. When you are trying to prevent items from becoming brittle you would be adding moisture to the air by means of a humidifier. When you need to take moisture out of the air to prevent books or papers from getting foxed or mold or mildew, you do that with a dehumidifier. You can measure the humidity in your room or library by purchasing an instrument called a hygrometer. Below is an example of foxing. Light eventually fades inks and even leather. It quickens the chemical decomposition of many materials. Windows and artificial light sources may need UV protection, like screens or filters, which have to be changed periodically.   When displaying books, it is a good practice to keep those that have the same bindings together. For example, if you have a four volume set of Napoleon’s works and separate them for decorative purposes, you might discover significant changes in the conditions of the books in a few months. The separated books could show a difference in the toning or color of the leather on the binding due to the different amounts of natural or room lighting in which they have been exposed. The differences become very noticeable when the books are put back together. Therefore it is always a good idea to keep like bindings and sets together. AMBIENT LIGHT. When overexposed to light, some leather bindings will fade as well as individual colors that fade more easily than others. For example, green and purple bindings are notorious for turning light brown. Many times you will see a set of green or purple books where the boards are still green or purple, but the exposed spines will have turned brown. Spot lights and strong artificial lights also contribute to significant fading of books. Visible radiation should be no more than 200 lux. UV radiation should be under 75 lux. Incandescent light is the lighting source that will create fewer problems, but one must be careful because it passes off more heat than other forms of lighting. Fluorescent lighting throws off much more UV radiation than does the incandescent. In addition, it is important to note that leather bindings are very sensitive to atmospheric pollutants such as sulphur dioxide. Basements, cellars, garages, and attics are not the place to store or keep books of any value. Nitrogen dioxide, sulfur dioxide, and chlorides are gaseous air contaminates which can affect the condition of books. Most gaseous pollutants can be eliminated with an activated carbon filter. Smoking should never be allowed around books as the tar and nicotine are damaging to the pages and over time will darken the pages and bindings.

It is always a good idea to keep like bindings and sets together. When overexposed to light, some leather bindings will fade...


The single greatest contributing factor to book damage is poor or improper handling of your books. When handling leather bindings or antiquarian books, hold the book in the center of your palm so that when opened, the covers rest against your thumb and fingers. Never let the boards (i.e. the covers) of the book drop open. They must be supported at all times. The hinge or gutter of a book cover can actually crack or tear causing the cover to actually break off of the book. Books when dropped will break. If you carry too many at one time and drop one on the floor, the likelihood of the cover snapping off is very high. Boards and spine covers that are yanked, pulled, or pried open too far will create too much stress on the hinge points of the bindings and cause them to break. Never open a book beyond the point of resistance. Forcing a book open flat will break its back. When removing a book from the bookshelf, be sure to pull the book from the center of the spine. never pull a book from the top or the headband. The majority of people do exactly that, causing the leather headband to break, tear, or pull loose. A fingernail can scuff or tear the headband or the leather around it as well. To properly remove or pull a book, simply push the surrounding books to the right and left of the one you are about to pull, allowing you the room to grasp the center of the spine on the targeted book or place your hand or finger over the top of the book and reach to the back (i.e. the fore edge of the book) and gently pull the book forward. The diagram we have provided demonstrates the “how to” and “how not to” pull a book from a shelf. With folio size books or books that are very heavy, use both hands. Always be sure your hands are clean. Good shelving is a must when storing books. Rough cut boards or unfinished wood can damage the sensitive leather on the bindings. Be sure your shelving does not have a lip or beading on the edges that will bump your bindings when pulling books off the shelf. Check for splinters, nails, staples, or any other protruding objects that could damage your books. Make sure the surface of your shelving is adequate. Tacky shellac, varnish, or poor quality, chalky paint will damage leather bindings as well. There should be enough space between each shelf to allow at least three inches of air flow space over the tops of the books. In addition, the depth of your shelves should accommodate the depths of your books. Avoid squeezing too many books onto one shelf. When packed too tightly, book hinges tend to break down. On the other hand, too few books on a shelf can also create problems, such as allowing the books to fall too easily. A sagging shelf will force books to sit unevenly and will contribute to the break down of the binding.



Insects are another major contributor to book damage when books are improperly cared for. Vermin love books. Among the worst villains are cockroaches, beetles, woodborers, silver fish, and moths. Certain materials present in the construction of books attract insects. There are easy precautions you can take to prevent insect damage to your books. A book’s natural materials usually attract a variety of insects. For instance, the sizing or the paste in books is made from wheat, attracting vermin also known as cellulose eaters. Preventative measures will go a long way in helping to protect your library from insect attack. Never leave food lying around. Always keep your library clean. Be sure cracks in the floor are sealed, holes in the wall or bricks are filled, and that your vents and duct work don’t have broken seams. Do not leave windows open without window screens. If you do develop a problem, take care of it immediately. If you see moths flying in the air three or four times a week, then you may have an infestation near or in one of your books. Often these moths come from grocery sacks that you have carried home. Moths lay eggs in the bags, you carry the bag home, the eggs hatch, and before long you have a major infestation problem. Usually, after finding the source, the problem can be easily eliminated. The location of the problem determines if it is an isolated situation or if many books are affected. Infestations can often be treated by wrapping the problem books and freezing them. Ask your conservator if it’s okay to freeze the affected book(s). If the book is multi-layered, like the boards of 1/2 and 3/4 leather bindings consisting of several layers of cardboard like materials, they will have different stretching or shrinking limits and freezing should not be done. If a binding is hand painted the paint will flake off if frozen. However, most bindings can be treated this way, killing the bugs within 36 hours. Cockroaches and silverfish can do extensive damage to a book by eating the book’s paste. Usually found on the surfaces of the books, they love the starchy adhesives. The woodborers, commonly known as “book worms,” tunnel through the pages and even the leather bindings. Upon seeing signs of cockroaches, silverfish, or woodborers on or near your books or shelving, contact an exterminator immediately. Usually this problem can be easily solved by a professional within 60 days. Beetles can be a nuisance and occasionally eat on books, but normally they are more interested in animal matter. Boric acid can dramatically reduce insect infestation. A little sprinkle on the shelves behind the books is most helpful. In addition to insects, rodents are also partial to books. These pests destroy books, not so much for their nutritional appeal but simply because they love to chew and sharpen their teeth. They usually attack the covers of the leather bindings or the fore edges of the book. If you see any signs of animal droppings on your shelves, call the exterminator immediately.



Evidence of mold or mildew like pink, reddish brown, or black spots on the pages of your book(s) indicate damage, and immediate action should be taken. First, try to determine if these spots have been there for many years, and it is an old problem which is now dormant or inactive. If the books are damp then wrap them in foil or plastic wrap and place them in a freezer (with the exceptions that we previously mentioned). If the books are soaking wet from water damage, then they should be dried out by blowing cool or slightly warm air across them. If the damaged books are valuable, then seek the help of a professional. If the books are not valuable, then it is not cost effective to restore the books. Restoration can cost more than the books themselves. But in any event, be sure to isolate these books from the rest of your collection. If you have a weather disaster or a plumbing accident at your home, contact an expert immediately. Remember to act quickly. Mold starts to grow within 24 to 36 hours. Remember when displaying your books at home or in your library to be mindful of where the water sources are located. It is never a good idea to display your books near a bathroom that may be located above or adjacent to your book display. A water source of any kind should be far removed from your books. Too often tubs have overflowed, showers leaked, or toilet tanks cracked, causing water leaks to the floor below, damaging many wonderful collections. If you display books in such areas it is a recipe for disaster!



DUST. It is important to dust your books several times a year. Dust is not only abrasive, it can even soil the inside or outside materials of your book. When dusting, use a feather duster or a dry, lint-free rag. Never use chemicals on the rag or feather duster. Never use commercial products like Pledge or Endust. When used gently, mini-vacuums can also be very handy. Be sure to cover the end of the hose or tube with a soft linen or muslin rag ensuring that if a small piece of leather is loose on your binding that it won’t get sucked into oblivion. PACKING. Many customers purchase leather books simply for investment purposes and never display them. Some display them, but eventually run out of room, forcing them to store a portion of their books. When storing books, do not lay them on their side. When shipping books, the opposite is true. Laying the books on their side is actually preferred since it will be for a short time only. Books stored for lengthy periods of time will have a tendency to warp if laid flat. So, whenever possible, store them in basically the same way you would if you had them on a library shelf, straight up. Do not lay them on their spine or on their fore edge. And remember, never expose your books to extreme heat or moisture, therefore avoid attics, basements, and cellars.



Opinions vary regarding book preservation. There are several book dealers who disagree with what I am about to tell you. However, I believe the vast majority would agree. Leather is made from animal skins, the skins of mammals. Leather has been around a long time, evidenced by a leather pre-historic bowl recently found dating back more than 5,000 years. Although leather is durable, through modern technology and industrial developments in the past three or four hundred years, mankind has added many airborne pollutants that contribute to the break down of the once, almost indestructible leather. We must now take preventive measures to protect leather bindings. There are two basic, but very different, techniques used in book preservation. First is to apply some type of treatment that helps prevent your books from drying out and cracking, and secondly, is to add pigment if necessary. Some book dealers believe that a book should remain as is. I do not hold that view. When a painter finished his work, a hundred, or even five hundred years ago, he probably had no idea that his painting would be enjoyed by countless people two or three hundred years later. This painting most likely would never have lasted to the twenty-first century had it not received some type of treatment. Museum paintings, in the Louvre or at the Sistine Chapel, have all had conservatory work done to them. The pollutants in the air darkened them so that you couldn’t see the paintings themselves, so they had to be cleaned or restored. Books, especially leather bindings, are not unlike paintings. They may need preservation treatment as well. Unless, of course, they are already in excellent condition and you keep them in the environment that we have written about. “Red rot” is a common and significant form of chemical damage affecting leather book bindings. The fibers break and completely turn to a brick-red powder. It is easily identifiable by the red dust coming off the binding. It is often noticed on clothes or a cloth the books are sitting on. Air pollution leads to chemical damage of bindings. A good example is combustible gas given off by a fireplace. This has been evidenced when one sees spines of books that had been untouched in a bookcase for a long time. The spines exhibit a higher acidity and higher sulphur content than the boards that have been protected by being against each other. Sulphur dioxide absorbed by the leather from the atmosphere is converted into sulphuric acid in the presence of an oxidant and erodes the book’s leather. Another form of chemical damage is photochemical degradation of leather. As we mentioned earlier in this chapter, light in general, and more specifically, UV sunlight, contributes significantly to the aging of organic material, leading to the decay or changing color of the leather. Another cause of damage to book bindings is the stretching and shrinking of the leather due to changes in relative humidity. Cracks may appear, and the grain will separate. This happens often to books bound in sheepskin. As the leather continues to breakdown, its ability to absorb or give up moisture decreases. So in an environment with lots of changes in temperature and relative humidity, this may lead to leather disintegrating. Since this book is about leather bindings and their values, it is important to understand what things can affect their values. Due to climatic conditions, leather bindings can have a tendency to dry out. If your book or books are dried out then you may consider treating your books with a solution containing 40% neatsfoot oil and 60% anhydrous lanolin. Neatsfoot oil is a lubricator used and recommended for use by book binders and conservators for many years. Lanolin, a wool fat, is also a lubricant, but more importantly, it has water retention qualities as well. One of the most popular leather dressings was developed by H. ]. Plenderleiths and is called the British Museum Leather Dressing. For years well informed dealers or bibliophiles have suggested everything from beeswax to Vaseline, saddle soap, coconut oil, olive oil, and paraffin, but most of these are too viscous to penetrate the leather deeply. Some actually seal off the leather so it can’t breathe, causing more damage than good. This is why it is important to use the proper kind of book treatment or preservative. We recommend the Museum Leather Dressing. When applying a dressing or treatment, the chemicals in these preparations can actually cause dust and dirt to penetrate even further into the leather. Therefore, be sure to remove any and all dust, dirt, and grime from the bindings before treatment begins. If your bindings are exceedingly dirty and have surface grime or dirt, a surface cleaning agent can be used to remove fixed dirt. In applying a treatment to books you should be very careful not to darken the color of the leather. Ninety percent of books will not darken. The camel or butterscotch colored bindings, blonde and very light colored bindings, and white vellum may have a tendency to darken. You may want to try an application of the treatment on a small area of the book that is not close to the spine and see how it looks. This treatment is important for the preservation of the book. When applying, give extra attention around the moveable hinges of the book. Now that you feel that you have a handle on book treatments, let me throw you a curve ball. Recently the Library of Congress warned that what they and many bibliophiles believed for years may not now be true. They state that if one has little experience in treating books or uses the wrong materials, it may do more harm than good. They caution that if too much dressing is applied or applied too often, the surface of the book could become tacky or sticky. Some dressings have been known to soak through the leather and stain the paste downs or end papers of the book, so be careful. Use sparingly, and when in doubt ask questions first. If your books are cared for properly and protected from harmful humidity, heat vents, and the like, then chances are they will be better off being left alone. However, if your humidity is not at around 50%, your temperature is not between 68 and 72 degrees or if they are already dried out or cracking, then you may need to be pro-active and treat your books.

Building private collections and appraising rare libraries since 1970