Jump back book
A jump spine book is a business book whose spine consists of several layers of weak cardboard glued together. This shape is used on thick books when the pages of the book are to lie flat.
Originally was jump back one only from the first to the last sheet position reaching back support, which was first developed in England. The current shape was not created until after 1850.
history
The so-called jump back book has been known around the middle of the nineteenth century. It was used in practices, law firms and authorities - wherever business data was constantly being handwritten. It got its name from the special spring mechanism of the book block spine, which ensures that the book lies completely flat after opening. This makes it easy to describe right into the waistband.
Manufacture
The production of this mechanism is performed by the bookbinding exclusively by means of paperboard and cardboard . First, however, you need a hand- stitched book block with a strong and well- glued curve. Solid lids are cut to match the thickness of the block.
The jump back should be made equally strong in several layers. The spine remains free from the block spine, but unlike ordinary books it is rigid. The transition from the jump back to the covers is the fold , which usually has a Kraft paper for reinforcement under the cover material . In the case of the jump back strap, however, a box, the so-called spring , lies in the fold and reaches back to just below the jump back.
When opening this spring presses on the first layers of the book block. The stable jumping back counteracts this force. As a result, the layers are pressed up to the maximum and the block paper falls to the side without bulging. As you scroll, layer by layer lies over the nib and remains flat.
opening
A jump spine ligament should never be opened from the middle. This is the most impressive way of demonstrating the jump effect, but the extreme stress on the spine of the book block that this creates causes it to lose its shape and sooner or later destroy the spring. If the tape is opened from the front or back and the pages are turned layer by layer, the mechanism is just as durable as the quality of its materials.
Furnishing
Because of its solid cover and its use as a business book, a simple cover material such as raw linen is usually used. Bound in half leather with corners and provided with a marble cut, but the chunky spring back strap can also be given a noble appearance.