What Types of File are Used and How do I View them?

All scanned images are known as "Raster" files. The standard type of file used for drawings and text is the "TIFF" file, although other file types may be used. This is usually compressed to reduce the file size. For colour images, a JPEG file type is usually used due to the larger amount of information to store. Raster files in mono or colour can be viewed and printed using "Imaging", the viewing and printing software already existing in Microsoft Windows '95, '98, NT, ME and 2000. (To find "Imaging", on your computer go to "Start", "Programs" "Accessories" and select "Imaging". This program is a "no cost" option in Windows 95 and fully incorporated within Windows 98, NT, 2000 etc).

For a mixture of documents, Multi-Page files are very useful. These involve one file name, which contains many images, (or pages) such as documents or drawings. Within "Imaging" for example, multi-page TIFF images can be viewed full-size or as "thumbnail sketches", i.e. a screen full of miniature documents. This makes the multi-page TIFF file eminently suitable for "job" or "project" filing where various documents of up to, say 50-75 images of A4 pages, A0 drawings, A3 charts etc., can all be filed under one project or job file name and viewed in "Imaging". The limitation is that only lineart TIFF images may be stored.

Multi-page TIFF files may be compressed or uncompressed similar to single files. Uncompressed multi-page TIFF files are very large but can include colour images. Compressed multi-page files usually use "Group 4" compression (same as fax machines) however, this type of compression only supports lineart (black and white) files hence compressed colour or greyscale images cannot be included within TIFF files.

Adobe "Acrobat" will also store and display multi-page files. This is a powerful program for storing and indexing both colour and mono images in the same file. Adobe "Acrobat" rapidly presents the chosen image from thousands of images in one file using its internal indexing system. Individual images may be inserted in the compressed format e.g. TIFF (Group 4), JPEG etc. For multi-pages files, with many images, this is the preferred choice. The file extension is .pdf and it is often known simply as a PDF file.