Tuesday 23rd September was a landmark day for the History Society as trustees were invited down to Lavenham Press to see our book rolling off one of their enormous Heidleberg ‘Offset Litho' printing machines, which was most informative and great fun; however, time now for a spot of education:
Since the 1960s, offset litho has become the most common form of printing technology for most types of high-volume books and magazines, particularly when illustrated in colour, as ours is; Lavenham Press were justifiably proud of their work, just as we are with our book.
Lithography originally used an image drawn with oil, fat, or wax onto the surface of a smooth, level lithographic limestone plate. The stone was treated with a mixture of acid and gum arabic, etching the portions of the stone which were not protected by the grease-based image. When the stone was subsequently moistened, the etched areas retained water and an oil-based ink could then be applied which would be repelled by the water and stick only to the original drawing. The ink would finally be transferred to a blank paper sheet, producing a printed page. In modern lithography, the image is made of a polymer coating applied to a flexible aluminum plate. The image can then either be printed directly from the plate (when the orientation of the image is reversed), or it can be offset, by transferring the image onto a flexible rubber sheet for printing and publication.
Of course, the whole process is just a little more complicated, because each image is separately produced by applying Yellow, Cyan, Magenta and and then Black inks, consecutively applied to each sheet of paper as it passes through each section of the massive Heidleberg press. Quite how each plate is lined up with all the others remains a bit of a mystery, but the end result is mightily impressive. However, the magic doesn't end there, because one pass through the press produced in our case getting on for 1,000 sheets each comprising 16 book pages - the machine is then switched into reverse to return the sheets back where they started, but the other way up. The whole process is then repeated and another 16 pages are printed together on the blank side.
We also learned that each pass through the press requires about 100 sheets to ensure the inks are evenly applied throughout the sheet, and the really interesting and tricky bit by the operator is to ensure the same 100 sheets are used for this process, to minimise waste - some very careful marking and machine control is obviously called for.
Our 600 copy book run (sadly all that £7,500.00 could buy, though of course the book comprises 352 pages so this is some 211,000 book pages in all)) is clearly not high volume for Lavenham Press. This was graphically illustrated when I enquired, whilst looking at a pile of our 16 page sheets being printed (a lot faster than anyone could possibly feed single sheets into a home or office printer) to be told that the press was only operating at half speed! Apparently operators only turn up the wick when the print run is about 15,000 or larger.
Impressive stuff, and all the more so when one realises that our relatively minor 600 copies will consume about one ton of paper - at which point we realised that our planned one or two trips by car to collect the printed and bound books had just turned into at least ten trips!
Not only did Lavenham Press invite us into the heart of their printing machine, but their staff were more than happy to explain what they were doing, how and why, whilst additionally being happy for us to take photographs - we cannot praise them too highly.
With fingers crossed, we are now hoping to be invited back again in the next day or two to see the by then even larger pile of double sided 16 book page sheets (comprising a single 32 page section) folded, sewn and glued together to form our book - we can't wait.
All that will then remain is to sell them to raise loads of money for preserving St Lawrence Church; this process begins in earnest on Saturday 4th October, when we will be launching the book in the church from 11.00 a.m. - more details to follow soon.