Size matters in the printing industry.
Everyone remembers the A4 exercise book from school. A colleague in the office might be looking for a B3 envelope. Or a DL brochure might drop into the mailbox. But while these terms are familiar to everyone in the printing industry, paper format names are a jumble of letters and numbers to most ordinary people. So here’s a look at how they came about and what they mean.
For centuries, there were different names for specific paper formats and repeated attempts to standardise them. In 1922, German engineer Dr. Walter Porstmann developed the DIN (Deutsches Institut für Normung) format system, which later became today’s ISO 216 international standard. Among other things, he defined the A format: a system with a ratio of 1:√2, allowing sheets to be halved proportionally without changing the aspect ratio.
The starting point for the entire series is the A0 format, with an area of exactly one square metre (841 × 1189 mm). Each additional format halves the area. So two A1 sheets make one A0 sheet, and so on down to A8 and sometimes even A10. This system makes the best use of space and simplifies production, because sheets of paper can be arranged efficiently and scaled for different applications. To this day, these standard formats make it easier to convert and process printed products.
A and B formats are the most important
In addition to the A format, there is also the B format, which broadens the range of paper sizes available in the printing industry. B formats are larger than A formats and are typically used for books, posters, or larger printed products that need extra space. B formats are the untrimmed sizes of printed sheets and are therefore suitable as packaging for the corresponding DIN A formats — which is why folders, files and envelopes are produced in DIN B. The maximum dimensions used by Deutsche Post, for example, are based on B formats.
Outside the norm: C, D, US
The C format is not part of the ISO standard, but is commonly used for envelopes because it is typically a few millimetres larger than the corresponding A format — so an A4 sheet fits perfectly into a C4 envelope. The D format has largely fallen out of use today. It can occasionally still be found in the shape of a DVD case.
Other special formats are used for specific printed materials such as greeting cards and flyers. There are also the US Letter (8.5 × 11 in.) and Legal (8.5 × 14 in.) formats used for office and legal documents in North America. These deviate from the ISO standard and do not correspond to the A and B formats.
Cost optimisation through coordinated formats
Choosing the right paper format is an important aspect of print production, both for cost optimisation and for a smooth production process. Standardised paper formats provide clear structure for the printing industry and can be easily distributed across different printing presses and sheet sizes. These formats are designed for most office and commercial applications and can be processed efficiently on standard printing presses. Standard sizes enable easy scalability and reduce costs by minimising trim waste through optimal sheet use.
For example, a B1 sheet (70 × 100 cm) can accommodate eight A4 or sixteen A5 sheets, making it possible to efficiently print a wide range of applications — from playing cards to stationery to exercise books. B1 and B2 sheets are easy to work with and deliver good material utilisation even for larger print jobs such as posters or packaging.
North American sizes: a challenge
Working with North America’s non-metric system can be a challenge on international projects, since US formats often require adjustments to ISO standard sheets to optimise layout. This is, at the very least, a cost issue, as it leads to increased paper consumption. This can be partially offset through careful planning of sheet usage and selecting the right sheet format — for example, if the press supports an oversized B2 format such as B2+, optimal use is also possible with US formats.
Economy and optimisation
Choosing the right paper format enables economical production and maximum flexibility. By optimising the combination of format selection, sheet size and cutting, printers can lower production costs and reduce waste — an important step toward greater efficiency.
Source: https://www.drupa.com/en/Media_News/drupa_blog/Print_Technologies/Size_matters_in_the_printing_industry_Standardised_paper_formats_for_efficient_production_planning