A technical guide to managing room humidity, protecting against ultraviolet light, and opening a hardcover binding without damaging the sewing of the spine.
Buying a limited edition is the beginning of a responsibility. A numbered book, a cloth-bound monograph, or a high-fidelity photographic portfolio is made with materials chosen to last, yet even the best materials can deteriorate if stored carelessly. A humid tropical climate, harsh sunlight, and our small daily habits quietly determine whether a book will still be fit to open for the next generation.
We put this guide together from our experience caring for the reading room collection and from the questions collectors ask most often. It is not a substitute for the advice of a professional conservator, but a set of basic habits that can be practised at home or in the studio without expensive equipment.
Invisible Enemies
Paper damage rarely happens overnight. It progresses slowly and is often noticed only when it is too late. There are five main causes to watch for: fluctuating humidity, excessive heat, light, dust and insects, and human hands. All five are connected. A damp room invites mould, mould attracts insects, and insects leave stains that are hard to clean.
Beyond external factors, paper can also deteriorate from within. Paper containing acid yellows and becomes brittle over time, and that acid can migrate to pages or other objects in contact with it. This is why art book publishers choose acid-free paper, and also why collectors need to be careful about what they tuck between the pages.
Temperature and Humidity: Stability Matters More Than Perfection
The range commonly recommended for a book storage room is a temperature of around 18–22°C with relative humidity in the region of 50%. These figures are not an absolute rule. Far more important is stability. Paper, cloth, glue, and board absorb and release moisture at different rates. When humidity rises and falls quickly, these materials expand and contract out of step, so covers warp, pages ripple, and spines are pulled.
In a tropical home, the biggest challenge is usually air conditioning switched on during the day and off at night. Changes like these are actually more harmful than a room that is slightly warm but stable. If possible, keep your collection in an inner room of the house, away from exterior walls exposed to the sun, bathrooms, kitchens, or basements. A simple digital hygrometer is enough to monitor the condition of the room from day to day.
If humidity is often too high, a dehumidifier can help. Make sure the air keeps moving as well, because still air in the corner of a closed cabinet is a favourite place for mould. Avoid storing books directly against a wall, and leave a little space so that air can circulate.
Light and Ultraviolet Rays
Light is the most easily underestimated enemy because its damage cannot be undone. Ultraviolet rays from the sun and from some types of lamps fade cover colours, especially coloured cloth and the ink on spines. A book displayed facing a window can lose the colour of its spine sooner than you might expect, while the parts covered by other books remain bright.
Place shelves away from windows, or install curtains and UV-filtering film on the glass. For room lighting, LED lamps with low ultraviolet emission are a good choice. If you like to display particular covers, rotate the books on display regularly so that light exposure does not accumulate on a single title. Watch out, too, for spotlights inside display cabinets, as their heat can dry out paper, cloth, and cover glue.
Shelves and Storage
Books of ordinary size are best stored upright, with other books or a bookend beside them so they do not lean. A book left leaning for a long time will end up with a twisted spine and a loosened binding. Nor should books be packed too tightly, because pulling one from a crowded row often tears the top of its spine.
Large, heavy monographs are safer stored flat, only a few titles to a stack, with the largest at the bottom. Stored upright, the weight of the pages pulls the text block down and away from its cover. Choose metal shelving with fully cured paint, or wood that has been sealed, because some types of raw wood can release acidic vapours.
Dust, Insects, and Clean Shelves
Dust is not just a matter of tidiness. Fine particles can hold moisture and feed mould, while dust that settles on top of the text block slowly works its way into the edges of the pages. Clean shelves regularly with a dry cloth or a soft brush, then brush the top of each book from the spine outwards while holding the book firmly closed.
Insects such as termites, silverfish, and cockroaches love rooms that are dark, damp, and seldom disturbed. Check your collection periodically, especially the backs of shelves and books that have not been opened for a long time. Warning signs include small holes in covers, fine powder at the base of a shelf, or bite marks along the edges of pages. Avoid spraying pesticide directly onto books. If an infestation has spread, seek help from professionals who are used to handling paper collections.
Boxes, Jackets, and Protection
An acid-free archival box provides layered protection against dust, light, and sudden changes in humidity. For special editions, a hinged clamshell box that opens like a book is very helpful, because the book can be lifted out without being pulled from a narrow gap. Clear covers made of stable polyester are also safe for protecting dust jackets. Avoid cheap plastics with a strong smell, as they can release substances that damage ink and paper.
There are a few things that should never be left inside a book:
- Newspaper clippings, because newsprint quickly turns acidic and leaves brown stains.
- Dried flowers or leaves, which can attract insects and leave marks.
- Metal paper clips, which can rust and stain the pages.
- Adhesive sticky notes, whose glue dries out and sticks to the page.
- Rubber bands, which eventually melt or turn brittle and leave traces.
Opening a Thick Edition
A new sewn book with a linen cloth spine needs to be introduced to the hands of its reader gradually. Opening it wide in the middle straight away can strain the sewing and crack the glue in the spine. The method bookbinders recommend is quite simple. Stand the book on its spine on a table, lower the front and back covers slowly until they lie flat, then lower a few pages from the front and a few from the back in turn, pressing gently near the fold, until you reach the middle of the book.
When reading, use a book cradle or two small cushions so the covers are not forced open flat on the table. A thick art book is simply not designed to open completely flat. Let it rest open at a comfortable angle, and if you need to hold the pages down, use a soft fabric weight filled with beads, not hard objects or a hand pressing on the spine.
Hands and Small Habits
Many people assume cotton gloves are a must when handling rare books. For paper, many conservators actually recommend clean, dry hands, because gloves reduce the sensitivity of the fingers and make thin pages easy to snag or tear. Wash your hands before reading, avoid lotion, and never lick your fingers to turn a page.
Other small habits also shape the lifespan of a book: not eating or drinking near the collection, not marking pages by folding their corners, and using a soft pencil if you really need to make notes. Take a book from the shelf by gripping the middle of its spine, not by hooking the top of the spine with one finger.
Recording and Knowing Your Collection
A good collector is also a good record-keeper. Keep a simple note for each title: the edition number, the date and place of purchase, its condition on arrival, and any changes observed over time. Photograph the condition of the book periodically. Records like these are useful for insurance, for valuation should the collection one day be passed on, and for detecting problems early.
For collectors with many titles, a personal catalogue also makes rotating displays and routine checks easier. You can note which books were checked last, which need to be moved into boxes, and which should go to a conservator. The habit sounds administrative, but it actually makes caring for a collection feel lighter, because a large task is broken into small, regular steps.
Lending and Moving Books
When lending a book to a friend or bringing it to a discussion, wrap it in acid-free paper or a clean cloth, then place it in a rigid bag so its corners do not get bent. Never leave a book in a car parked in the sun, because the temperature inside the cabin can rise far beyond that of an ordinary room and soften the binding glue. Include a short note on how to open the book safely, especially for editions whose spines are still stiff.
When Damage Has Already Occurred
If you find spots of mould, separate the book from the rest of the collection, leave it in a dry, airy room, and do not wipe it with a damp cloth. If a book gets wet, dry it slowly in the open air, standing upright with its pages slightly fanned, and slip plain absorbent paper between some of the pages. Do not use a hair dryer or leave it in direct sunlight. For tears, do not use ordinary sticky tape, because its adhesive yellows and is very hard to remove. Damage like this is best handled by a paper conservator who can choose repair materials that are safe and reversible.
Caring for a book is not about keeping it new, but about making sure it can still be read, opened, and passed on.
The principles above become even more important for photographic collections and archival reproductions, whose tones are delicate and easily altered. The monograph Arsip Visual Hindia Baru: Dokumentasi Lensa 1920–1940, for instance, is printed in tri-tone on thick archival cotton paper, and will keep its tonal depth longest when cared for in the ways described in this essay.
