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

[Daniel Sabo <danielsabo gmail com>]

32bit floats have a precision of 24bits*. The exact size of the ulps**
(unit in the last place) in the range [0.0, 1.0] is more complex
because the exponent will give you more precision as you approach 0.
This gets even more complicated because actually doing any math most
likely gives you some rounding error, e.g. the gamma conversions are
not precise to 24bits but are to more than 16bits.

We have never done an error analysis of the entire gimp pipeline, but
16bits is already beyond human perception (in my unscientific
opinion). The real value of using floating point is that it can hold
out of gamut values.

* 
https://en.wikipedia.org/wiki/Single_precision#IEEE_754_single-precision_binary_floating-point_format:_binary32
** https://en.wikipedia.org/wiki/Unit_in_the_last_place