A large book is clumsy to hold and difficult to manage. You will rarely do large drawings outdoors and in any case it is not advisable to do so.
They take too long to complete, for one thing, and for another the labor involved takes out all the enjoyment. Large drawings are best done in the home or studio. Also a large sketch book will not fit into your satchel and will have to be carried separately. This is a tiring and unnecessary thing to have to do and as you have a satchel you may as well use it for carrying everything.
A small book does not give you any scope for painting or for drawing. If you have an eye for lots of detail you will be cramped. If you like to slosh your washes about yon will feel constricted. It is irksome to be limited by a small page. A medium sized book, say one about 14 in. X 9 in., will allow you the freedom to make larger drawings by covering two pages, or smaller by using only half or a quarter of a page. A good rule to apply when choosing the size of your sketch book is that it should fit snugly into your satchel, be easily taken out or put back and doesn’t rattle like a dried pea in a pod amongst the other items of equipment in the bag.
The smaller sketch book, one that can fit into your pocket, is useful for quick notes and scribbles, while waiting for a train, or sitting in a cafe or park where you wish to be inconspicuous. For this purpose it can be quickly hidden and easily carried about. It is a good idea, anyhow, to have a small notebook in your pocket all the time for taking down quick impressions and for noting ideas. It is good practice and can lead to some interesting observations, especially where drawing people is concerned.
You can buy sketch books at all the leading art stores in sizes ranging from 5 in. x 4 in. up to 12 in. x 18 in. Some have a spiral binding for ease in turning over pages; others are more like ordinary books. The difficulty will not be in choosing the right size but in choosing the right surface. The ideal book will have both smooth and rough paper, thick and thin paper and even tinted papers ready for every contingency which may arise. Unfortunately it hasn’t been marketed yet, but if you are willing to make up your own sketchbook you can have one. And it is really quite simple to do.
Buy as many different types of paper as you think you might like to use – say one or two sheets of each type – cut them neatly into a handy size, punch two or three holes along one of the edges. Do the same to two pieces of firm but light cardboard for backing and clip the whole together with spring clips that you can buy at any stationer. The backing can be a little larger than the paper if you wish. Making your own sketch book gives you far more freedom of choice as regards the type of surface on which to tryout your drawing. Not all surfaces will suit your style and with your own made-up book you have the opportunity to find out which suits you best.