An image defect in the printed image in which separate layers of colour appear on an area of the image where two colours meet. A technique used to reduce the size of a data file, thereby reducing the amount of disk space required to store the data file or the time required to send a file. A compressed image must be decompressed to be viewed or used. While compression is advantageous for storing or transmitting an image, it can cause degradation of the image even after it is decompressed. The difference between elements in a photograph.
Contrast can include the difference between light and dark areas, or a marked difference in colours.
The use of a coding technique to reduce the volume of a stored data. The zone of in-focus elements, from front to back. Another way to put this is the range of distance that is acceptably sharp within a photograph. Depth-of field varies inversely with the aperture opening. The opposite of analogue.