The color components are stored in the half-float format,
i.e. in a 16 bit value, with 5 bit exponent, 10 bit mantissa
and a sign bit. See also OpenEXR for a format
employing half-floats.
The color components are stored in the IEEE single-precision
floating point format, i.e. in a 32 bit value, with 8 bit
exponent, 23 bit mantissa and a sign bit.
The color components are stored in the IEEE double-precision
floating point format, i.e. in a 64 bit value, with 16 bit
exponent, 47 bit mantissa and a sign bit.
