If you are not experienced in buying or producing print, it can be quite bewildering when a set of printers’ proofs arrive on your desk. You may think you have ordered a simple 16 page A4 brochure with a nice heavy cover so have a reasonable idea of what to expect from the proofs, but they arrive appearing to show pages next to each other in the wrong order, or, upside down in relation to each other, or duplicated (sometimes more than once) on the same sheet. Do these guys know what I’m trying to get produced here?
The reason for this is that printers who work with large sheet sizes have a number of techniques for making most efficient use of plates and paper, which determine how jobs are laid down, or planned. And we are sometimes asked to explain why we have put the pages in the order we have. So I’ll try to do that here.
At PrintHouse Corporation, we work mostly with SRA1 sheet sizes, which means we can plan a job with 8 A4s to view on an oversize A1 sheet. There are then three main methods of working to produce the job most efficiently. These are:
Sheet work
On multi-page work such as books, brochures or magazines, the most efficient way of printing is “sheet work”; which means printing one side of the sheet with one set of pages, and then printing the reverse with a different set. For example, a 16 page A4 document would require 2 sets of plates, with 8 pages printed to the front and the other 8 printed to the reverse. Depending on how the job is to be finished, these sheets are then folded to create a 16 page section. And the way the job is to be folded will determine where the pages are placed on the sheet – which is why it will almost never look the same as the pages when viewed on screen, or in the finished booklet. This principle is just extended for longer documents, so that, for example, a 128pp A4 document will be laid down as 8 sheetwork sections of 16 pages per section.
Work and turn
However, not all jobs conveniently end up the ideal length for printers. So the next approach is to “work and turn” the sheet, which means printing 8 pages on one side of the sheet, then turning the paper over left to right and printing the same pages on the reverse. Providing these pages have been laid down correctly, this can give an 8 page section on each half of the sheet, so that it can be cut in half to provide 2 copies of the same 8pp section from each sheet. The advantage of printing like this is that only one set of plates is required to produce the work, and it is the most common means of producing all types of printing where the paper area available is equal or larger than the final image area required. So if, for example, we only wanted to produce one double sided A4, we would normally put 4 fronts on one half of the sheet with 4 reverses on the other half, and then print sufficient sheets to give us the required quantity, divided by 8.
Work and tumble
Some pages don’t lend themselves to work and turn – usually because they are larger in size than the measurement of the sheet from front to back. In this case, the last option open to us is to work and tumble the job – which means printing both sides of the page or pages on the same sheet, but laid down in such a way that by turning the sheets over front to back, rather than left to right, we can back up the appropriate pages with their correct reverse.
The type of imposition that will be applied to your job is decided between the sales and repro department before the production stage so that we can ensure the most cost effective solution for your individual requirements. You don’t need to worry about the folding; we’ll do that. You just need to check the colour and content carfeully, safe in the knowledge that whatever the imposition looks like with regards to folding, as long as the content is correct, we’ll handle the rest.
