The Digital Dungeon

File size is important when you are trying to make an image available on-line because it has to be good quality enough that it’s useful, but small enough that it can be loaded into a browser without having the patron wait. Also, if you want to archive the images, then you want a high quality archival image without being too hefty on memory. There are a few things that affect file size: The type of file affects file size. See the post about file types . Whether you are saving in full color, grayscale, or black and white also affects it. Typically, full color images are going to be large files. Grayscale is slightly smaller, but still much greater than black and white. However, you have some options when saving in full color or grayscale. 8 Bit or 24 bit Color/Grayscale You can save a color or grayscale image as either 8 bit or 24 bit color or grayscale. 8-bit 8 bit means that there are 8 bits that describe each pixel. This means that you have 256 different combination of bits to s...

File Formats What format you use is dictated by your goal. Libraries have a tendency to want to have a small access copy of reasonable quality, and a high quality archival copy of reasonable file size. To get a better idea of what the different formats are, and what they do, I've linked to some articles: TIFF (Tagged Image File Format ) JPEG JPEG2000 PDF JPEG is the perfect format for full color or grayscale images because it provides a nice balance between quality and file size. The format is stable as long as you do not edit the file over and over. If you are going to be editing the file, save it as a Tiff first, then save it as a JPEG. JPEGs are perfect for access copies, and sometimes for Archival copies. A full color or grayscale Tiff is huge as far as file size goes. A black and white Tiff, however, is generally smaller than a black and white JPEG. Don’t ask me why. Tiff also provides the best quality and stability. You can use Tiffs for archival storage if you have a...