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Memory requirements

The memory requirements for image data in a Calamus document can be calculated using the following formulae. The result is the storage requirement of the picture in bytes.

For black and white or two-colour pictures (usually compressed in the document):

• Round up the number of horizontal pixels to a multiple of 16
• Divide the result by 8
• Multiply the result by the number of lines in the picture

For greyscale pictures and those with 256 colours:

• Round up the number of horizontal pixels to the next even number
• Multiply the result by the number of horizontal lines

For RGB and CMYK colour images:

• Multiply the number of horizontal pixels by the number of lines
• Multiply the result by four

Example:
A greyscale TIFF has a 935 * 1,111 pixel resolution. It will occupy 936 * 1,111 bytes = 1,039,896 bytes in memory. A TrueColor image of the same size will require four times this amount.