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A shortened name for binary digit 0 or 1. This is the smallest unit of digital information used by a computer or digital camera.
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The amount of colours that can be captured by the scanner : 24-bit is 8-bit red, 8-bit green and 8-bit blue, giving a total of over 16 million colours. Most of the latest scanners have 30-bit or 36-bit, to capture billions of colours. In practice it's very difficult to see any difference once you go beyond 24-bit.
The number of bits used to represent each pixel in a digital image. This figure suggests the image colour or tone range.
A digital image formed by a grid of pixels. The computer assigns a value to each pixel - ranging from 1 bit of information black or white) to as much as 42-bits per pixel.
An area of internal memory that temporarily holds reusable data to ensure a faster access time. Large programmes, such as PhotoShop, require quite a bit of cache, otherwise they get very slow.
Often quoted on scanner specifications to indicate the maximum tone range that the scanner can capture. A higher figure indicates that the scanner will capture more detail from the highlights to shadows. With flatbed scanners that are being used to scan prints this isn't too important because the tonal range has already been reduced in the printing process. A higher dynamic range is essential on film scanners when scanning transparencies that have a wide tonal range. Specialist films, such as Fuji Velvia, are said to have a range of around 3.7D, so the scanner needs to have at least the same dynamic range to ensure every bit of highlight and shadow detail is captured in one scan. Also see "High Dynamic Range"
This is used to describe 24-bit colour mode that can produce as many as 16.7million colours, creating a ‘true colour’ image.