N-up and imposition, what do they mean?

Have you ever heard of imposition? I hadn’t. Printing, like all industries, comes with its own unique terminology to learn and concepts to understand. Imposition and N-up were some of the first terms to stop me in my tracks.

Then click, a simple explanation and I totally get it.

Question – “What does N-up imposed mean?”

Answer – N-up imposed jobs collate multiple pages onto a single sheet for printing, folding and finishing. The ‘N’ stands for number and tells us how many pages have been imposed onto a single sheet. Once we know how many pages have been imposed, we can drop the ‘N’ and simply use the number followed by ‘up’ i.e. 2-up, 4-up, 8-up etc.

Figure 1.The above illustrates a 4-up imposed leaflet (front and back). This shows the printers spread (read below). Once printed, folded and trimmed, this will create an 8-page booklet from a single sheet of paper.

Question – “What is imposition?”

Answer – Imposition is the method of arranging N-up’s multiple pages so that, upon printing and folding, they run in the correct order. The method of imposition will vary depending on the number of pages per sheet, i.e. how many ‘up’ the job is.

Question- “How is it done?”

Answer – Originally, when pages were formed of moveable type, imposition was done manually with pages being set in a chase before printing. Subsequently, pages were arranged on film then stripped and combined to produce the required imposition. The advent of plate-setters allowed an entire spread to be imposed onto a single plate ready for printing.

Moveable type held in a printers chase

Today, almost all imposition is carried out digitally for greater accuracy and speed.

Question – “What’s a printers spread?”

Answer-The printers spread demonstrates imposition as seen before folding, with pages out of sequence but imposed ready for printing. See figure 1 above for an example.

Question – “So what’s the readers spread?”

Answer-The readers spread shows the final printed version after folding and collation so that the pages run in numerical order as they would in the final piece.

Once someone breaks it down, N-up jobs and imposition are actually quite simple. It’s all about printing the pages you need in the most economical way possible, ensuring the final product is in the right order for the reader.