Scanning, used to check a proof without reading it word for word, has become common with computerisation of typesetting and the popularisation of word processing. Many publishers have their own proprietary typesetting systems, while their customers use commercial programs such as Word. Before the data in a Word file can be published, it must be converted into a format used by the publisher. The end product is usually called a conversion. If a customer has already proofread the contents of a file before submitting it to a publisher, there will be no reason for another proofreader to re-read it from copy (although this additional service may be requested and paid for). Instead, the publisher is held responsible only for formatting errors, such as typeface, page width, and alignment of columns in tables; and production errors such as text inadvertently deleted. To simplify matters further, a given conversion will usually be assigned a specific template. Given typesetters of sufficient skill, experienced proofreaders familiar with their typesetters' work can accurately scan their pages without reading the text for errors that neither they nor their typesetters are responsible for.