There are many file types which are designed for digital images. JPEG is actually a collection of many different algorithms. One of these, a descendant of JPEG 2000, is a “loss-less”. This means that a 80 MB digital image can be compressed to 3MB without loss of data. We use this particular JPEG compression on all the slides we scan. When we scan your slides, the image starts out as a 80 MB file, and ends up on the disk we send you as a 3 to 5 MB file. If you load these images into a high-end photo editing program (like Photoshop CS6) the image size grows back up to 80 MB. It’s like magic, and it’s why we use JPEG file types.
|RAW||This is an image class, not a file type. It refers to files that have all the original image data. The most popular file types in this class are TIFF and DNG.|
|TIFF||Stands for Tagged Image Files. No compression, no loss of fidelity, big files used by professionals. This is a rather old file type. It’s actually intended for raster (Thanks Galen!) image files.||Use only if you have special needs.|
|DNG||Stands for Digital Negative Graphics and based on the TIFF format. A DNG file contains the data (raw images data and metadata) needed to render an image without needing additional knowledge of the characteristics of the camera.||Use only if you have special needs.|
|PNG||Stands for Portable Network Graphics. This is a very old standard. It uses compression and has color depth greater than human perception. However, file size and image quality are inferior to JPEG.||Do not use.|
|GIF||Stands for Graphics Interchange Format. This is a very old standard. It is limited to 256 colors.||Do not use.|
|BMP||Stands for Device Independent Bitmap. This type has adequate color depth and resolution for images, but is inferior to the RAW class of the types ,while file size is similar to the RAW files types.||Not intended for photographers.|
|JPEG||Is the acronym for the Joint Photographic Experts Group, who invented this format. Introduced in 1992, this standard is continuously updated with the latest revision published in 2008. It uses compression with good image characteristics.||Use this with 80% compression|