Why Does Your Book Cover Curl Up in the Monsoon?

The rains pattering on the window sill, a hot cuppa and a cosy book to read. Sounds like the perfect monsoon escape. But put the book down for a couple of hours and suddenly the cover curls up and a couple of pages look warped. How annoying is that!

Have you wondered why this even happens?

Well, the culprit is commonly the extra moisture in the air during the rains.

Books are mostly made of paper, which contains cellulose fibres. Paper is hygroscopic. That is just a big word which means paper absorbs and releases moisture from the surrounding air.

During the monsoon, when humidity rises, the paper absorbs the moisture from the air and as a result expands. When the expansion is not balanced, it results in the book cover curling.

This is because the cover is often laminated with plastic or varnished from the front (that matte or glossy sheen that you see or feel) but the back of the cover does not have a lamination or varnish. This creates an unequal distribution of the absorbed moisture, where one side of the cover absorbs more moisture and expands whilst the other side does not. This results in the book slowly curling up.

The photo above, you can see how one of my favourite reads has curled up. I read it a few times and left it on the shelf. The July-August rains have been incessant this year where we live and the humidity has taken a toll.

So first things first. How do we straighten this out?

Here’s one way to do just that.

Lay the book on a flat and clean surface. Place a board on the book. Then place a heavy weight on top in such a way that the pressure is distributed equally.

In the photograph above, I have used a clean and dry wooden chopping board to place on the book. I first placed a clean cotton cloth between the book and the board to create a protective layer. This reduces the chance of the wooden board staining the book cover by mistake. I opened out dumbbells and placed both the weights at an equal distance on the board so that the weight was equally distributed.

Leave it for two days under even weight and check if the cover has flattened out. If it hasn't then leave it for an additional day. Make sure the weight is not excessive because too much weight may damage the spine of the book.

So once we fix this, how would we prevent this from happening?

So the first thing to think about is how and where we store our books. On a rack or a shelf, that is not as important as making sure the books are in a dry and stable area away from moisture.

For books stored upright, keeping them reasonably snug on the shelf can provide support. I have seen books that sag on the side or the spine bends if not tightly shelved. For particularly fragile or valuable books, protective acid-free enclosures can provide an additional layer of protection.

Then there is the monsoon.

If we pick a book out of our shelf to read, we must place it back tightly shelved. If the book is lying on the table or bed, then the moisture in the air will be soaked up by the papers. Another neat trick is to store the books horizontally so that gravity does its work. Keep the books tightly shelved and pressed together. Changing climatic conditions can also affect our books. Moving a book from a dry environment into a humid one can expose it to a sudden change in moisture.

Some of us love to read during our travels. The different climatic conditions play a role in damaging our books. To avoid the excess moisture situation, the best thing is to take hold of a Ziploc bag, place the book and along with it a few packs of Silca gel.

In the picture below I have placed around 4 packs of silica gel. I pushed out the air carefully and then zipped the bag shut. I could see a difference by the end of the day.

The important thing to remember is that silica gel works by absorbing moisture from the enclosed environment. It is a useful travel aid, but it should be used thoughtfully. Remember, a damp book sealed inside a plastic bag can trap moisture resulting in damage instead of protecting the book.

A little care goes a long way

Books are made of materials that respond constantly to their environment. Understanding how moisture affects paper helps us make changes that can protect our favourite reads.

So, during the next monsoon, when the rain is tapping against the window and the perfect book is waiting beside your cup of tea (or coffee), remember to give the book a little care too.

Author's Note

Kiran Java has academic training in preventive conservation through the Post Graduate Diploma in Preventive Conservation offered by Bhandarkar Oriental Research Institute (BORI) in collaboration with the Indira Gandhi National Centre for the Arts (IGNCA). The insights shared in this article are intended to contribute to a broader understanding of caring for collections and cultural property. For more information you may email: kiran@kiranjava.com