Digital conversion is the process of scanning physical mediums into digital formats. Something is considered digital if it is electronic and can be stored and viewed on a computer. The most common digital formats for conversion are TIFF, PDF and JPEG. Most people have heard what these are, but may do not fully understand the exact differences. Determining the best format depends on the situation, so let’s review each format including the similarities and differences.
JPEG stands for Joint Photographic Expert Group. This format was developed in the 1980’s specifically for the storage of photographic images. JPEGs are bitmap images that consist of a matrix of tiny dots or pixels. Pixels are one of the simplest and most efficient methods to present a digital image, so JPEG files tend to use less memory than TIFF or PDF. Because a JPEG is a bunch of pixels of fixed sizes, the image tends to get “fuzzier” or less defined as the image is enlarged. JPEG images can also be compressed in file size with minimal visual loss of resolution. This is largely because the human mind tends to “fill in the blanks” if certain colors or shades of pixels are removed. JPEG images are also good for images that have a wide range of color spread over the entire area. JPEG files are very common on the web because of its simplicity of format, breadth of color presentation with relatively small file sizes. JPEG files tend to lose resolution as they are edited.
TIFF stands for Tag Image File Format. TIFF files are vector images which rely on mathematical algorithms rather than pixels or dots. Because a TIFF is primarily presented by a series of algorithms, a lot more information can be contained in a TIFF, such as several layers of an image. It is for this reason that TIFF files tend to be much larger than JPEG. TIFF files can be enlarged without loss of resolution. TIFF graphics are used in the printing industry because of the high resolution capability. They normally can’t be presented on the web because of the browsers limitation in interpreting TIFFs.
PDF stands for Portable Document Format. PDF was developed by Adobe, and tends to be the most widely used format for documents. PDFs can incorporate embedded images as well as recognizing fonts and characters. PDFs are most commonly used to capture and store multiple page documents where a user can navigate and view it as they would a magazine or book, only in electronic format. One caveat is that that when a document is first scanned as a pdf, the text and fonts are not electronically readable. In order for a pdf to be electronically readable (i.e. you can search and manipulate characters) a secondary processing using Optical Character Recognition (OCR) technology is needed to convert pixels into characters. More info on OCR. Once OCR converted, PDFs are a powerful medium for storing and retrieving multiple page documentation.
When to use TIFF vs. PDF vs. JPEG
One could take a one page object and scan it to any of these formats and they would all perform basically the same function; to present an electronic image to a human viewer. However there are a variety of factors to consider in choosing the best format to meet your needs.
PDFs seem to be a natural fit for multi-page documents, especially if there is a desire to read and search by characters. Most computers come equipped with a pdf reader. PDF files can be easily presented on a website and can even be compressed to minimized download time. Usually the largest memory hog on a PDF is high resolution graphics. While a single image can be embedded in a PDF, the file size is usually larger than the corresponding image file because of the inherent features of a PDF.
If the scanned object (paper or microfilm) is fairly simple and higher resolution is not needed, then JPEG would be the most cost effective medium because it normally takes the least amount of memory when compared to TIFF or PDF. So simple (one sheet records) might use JPEG. When scanning and storing thousands of images, file memory can be a huge consideration.
IF high resolution and detail is a priority then TIFF is probably the best choice because a tiff file can be magnified without losing resolution. So for drawings or specifications where it is imperative to see and interpret every fine detail, TIFF would work the best.
So in short, the best format depends on size of job, resolution requirements and type of object that is being scanned.