From 2002-2004 an important innovation was developed, in support of the creation of new Project Gutenberg eBooks. This was Distributed Proofreaders, an early example of what is now known as crowdsourcing. Through Distributed Proofreaders, volunteers engage in a portion of the eBook creation process — whether it is copyright clearances, proofreading (a page at a time!), or formatting, checking, and finalization before uploading. Those portions, when coordinated together, lead to the creation of new eBooks from printed sources. Distributed Proofreaders has become the single largest source for new eBooks to the collection, accounting for approximately half of all titles. Distributed Proofreaders has also innovated substantially in the use of HTML+CSS (cascading style sheets) for very attractive presentation of eBooks in Web browsers. SCANNING By the early 1990s, scanning and optical character recognition (OCR) started to become widely available. Hart received a full scanning station via a grant from a computer manufacturer, which was used to produce several of the first 100 eBooks. The scanner was a flatbed model, which required the user to hold the book open, scan a page (or pair of pages) for ingest to the OCR software, then flip to the next page. The OCR software would then automatically recognize the characters from the scan, and create an editable view of the text. Proofreading and formatting would then occur in the same way as for a typed text. A few years later, Project Gutenberg worked with Distributed Proofreaders to acquire sheet-fed scanners. These scanners, which are still in operation, are faster. They also tend to produce an image that is properly aligned, versus the skewing that sometimes occurs with flatbed scanners. An important difference is the printed books are damaged: prior to scanning, the spines of the books are cut off, in order for the individual pages to be ingested by the scanner. [Illustration: 0006] Figure 3: Image from the Doré illustrations of Dante’s Inferno It has been Project Gutenberg’s intention to make all the original images from the scanners available, alongside the finished eBook. This is to have a more complete record of the eBook’s source(s), and also to facilitate improvements by finding typos. Most eBook producers to date have chosen to not provide the scans, however. Scanners are used for images within printed books, which are typically included as JPEG, GIF or PNG items within HTML and other formats. Inline images may be at a lower resolution, and then clickable to obtain higher resolution images. Color scanners are used, whenever possible, for color images. Project Gutenberg has no prohibition against using items scanned by other parties. Several excellent sources of scans are freely available, including Google Books, Gallica, and The Internet Archive. Scans, and raw OCR output (if available), may then be transformed into Project Gutenberg eBooks by volunteers.