JPG is a image file format and PDF is a document file format. PDF files can hold images as well as text. Both of these file format are very portable and is used as preffered file format in many occations.
JPG is a common file format used on Scanners and Digital Cameras. The reason is that JPG format allow high compression of image data without loosing much of it's perceptive quality.
PDF is another very common file format. It is the predecisor of PostScript and allow much higher quality when it comes to printing documents.
JPG and PDF are two of most widly used file format. Virtually all operating systems and browsers support these formats out of the box.
JPG's are often used for web sites and email as they are generally smaller file sizes as they are lossy meaning that some image quality is lost when the JPG is compressed and saved. The resultant 'lossy' file means that quality can never be recovered. The JPG format is often used in digital camera memory cards. The JPG file is a great format as it often manages to compress files to 1/10 of the size of the original file which is especially good for saving on bandwidth.
JPG is a popular graphic format, which is characterized by a high degree of compression, which leads to a decrease in image quality. It uses the technology of encoding of smooth color renditions, providing the ability to reduce the amount of data frequently during the recording of the image. Because of the small size it is requested by the owners of websites, allowing you to save the traffic effectively. It is also frequently used in memory cards of digital video cameras. The JPG algorithm is optimally suitable for compressing photographs and pictures, in which realistic scenes with little contrast of colors are present. It is not recommended to use this format for compression of drawings and various kinds of graphics, since a strong contrast between a number of closely located pixels provokes the appearance of visible artifacts.
JPG is a graphical file format for editing still images, it offers a symmetrical compression technique which is processor intensive and time consiming in both compression and decompression. JPEG is a joint standard of the International Telecommunications Union (ITU-T T.81) and the International Organization for Standardization (ISO 10918-1). JPEG involves a lossy compression mechanism using discrete cosine transform (DCT). Compression rates of 100:1 can be achieved, although the loss is noticeable at that level. Compression rates of 10:1 or 20:1 yield little degradation in image quality.
The procedure for compressing the digital images in JPG format is carried out in several stages. First, the photo is transformed into a color space YCbCr, then it is divided into squares to determine the upper range of the color spectrum. Finally, the colors and brightness are coded. JPEG uses a "lossy" compression system and discrete cosine transform technology. The format acts simultaneously as the standard of ISO and the International Telecommunication Union. The file compression ratio is in the range from 10:1 to 100:1. In this case, the reduction in image quality can vary from insignificant to substantial.
The JPEG Committee
PDF is a file format developed by Adobe Systems for representing documents in a manner that is separate from the original operating system, application or hardware from where it was originally created. A PDF file can be any length, contain any number of fonts and images and is designed to enable the creation and transfer of printer-ready output.
PDF is a cross-platform extension, which is necessary for the visualization of printed materials in electronic form. It is created by specialists from Adobe Systems using separate PostScript resources. PDF documents can exist separately from the OS or hardware tools with which they were developed. Files of this format do not have restrictions on the length, number of types and image options, as they allow you to embed various multimedia tools, scan-line and vector images. They are supported by Adobe Reader and many browsers, providing the plugin is installed.
Each PDF file encapsulates a complete description of a 2D document (and, with the advent of Acrobat 3D, embedded 3D documents) that includes the text, fonts, images and 2D vector graphics that compose the document. They do not encode information that is specific to the application software, hardware, or operating system used to create or view the document.
PDF supports color models CMYK, RGB, shades of gray, and also it has its own technical formats for performing the exchange of finished documents. Any file contains a description of a 2D or 3D document with all the necessary components (scan-line, vector graphics, text and more). The extension does not encode data associated with the software or OS that is used to develop and view the document.