slide freely up and down the ramps 16 and 18 the top surfaces of 19 the ramps providing tracks for the platens a flexible web 20 spans the gap between the lower ends of the platens 12 and 14 as shown in fig1 the book 10 is open at its last page and one cover board 22 is resting on the platen 12 and the other cover board 24 and all the leaves of the book are resting on the platen 14 the spine 26 of the book is supported by the flexible web 20 because the book 10 is opened at one end the position of the platens 12 and 14 are not symmetrical the platen 14 is at its extreme lower end position and the platen 12 is in a raised position it will however be appreciated that if the book was opened at its centre and laid in the support then the positions of the platens 12 and 14 would normally be symmetrical about a centre line of the support fig2 shows how the flexible web 20 can be arranged the web is continuous and has one end clamped at the top edge 28 of the platen 12 the web then extends over the upper face of the platen 12 around the bottom edge of the platen and up the underside of the platen to a rod 30 the web extends over the rod back down behind the platen and across the gap between.