Re: [Gimp-developer] How precise is Gimp 32-bit floating point compared to 16-bit integer?

[Simon Budig <simon budig de>]

Elle Stone (ellestone ninedegreesbelow com) wrote:
> So real colors can easily fall outside the range 0.0 to 1.0 if they
> are converted to sRGB. What happens to the precision when dealing
> with RGB values up around 2.5 or down around -0.9?

Sign is stored in its own bit. Precision is not affected there.

Floating point numbers are represented as mantissa * (2**exponent),
So whenever the exponent gets increased by one you lose one bit of
"absolute" precision.

So for numbers up to two you have 22 binary digits of precision (after
the "dual" point), for numbers up to four you have 21 binary digits of
precision.

Bye,
        Simon
-- 
              simon budig de              http://simon.budig.de/