- The size of an uncompressed file can be calculated by
multiplication. In the two examples provided, determining
the number of "dots" or pixels is identical to
determining the area of a rectangle. Multiplying 8.5
inches times 300 dots per inch yields 2550 as the number
of pixels in each horizontal row; 11 time 300 yields 3300
for number of rows. The "area" is 2550 times
3300, or 8,415,000 dots or pixels. If 8 bits (1 byte) of
information are captured for each pixel, the uncompressed
file will have an extent of 8.4 million bytes; if 24 bits
are captured, the size triples to 25.2 million bytes. For
comparison, an uncompressed binary file (1 bit per pixel)
will have one-eighth the extent of the 8-bit file, or
about 1 million bytes. The term megabyte is used to refer
to 1024 times 1024 bytes (1,048,576), so 8,415,000 is
only 8.0 megabytes.

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