OpenEXR support

[flord]

It would be great if PhotoFlow could export images as OpenExr, with pixels brighter than diffuse white having values above 1.0.
Currently, when we export in tiff 32bit float, the entire dynamic range is compressed between 0.0 and 1.0, making the image very dark.
The OpenExr spec defines than an object reflecting 18% of light, exposed correctly, will have a pixel value of 0.18. So very bright pixels like highlights or light sources in the image have values well above 1.0. OpenExr also supports half-float, which saves space.
For example, this DNG image produces this exr image, with pixels in the sky reflection in the glass bowl being above 1.0

[aferrero2707]

I have opened an issue here to ask for EXR write support.

However, in PhF the 32-bit floating point TIFF output does not restrict the output range to [0, 1]. Here is an example of your DNG file opened in PhF, saved with a +1EV exposure adjustment: https://filebin.net/zejisryd19wbjxq3
The folder contains both the TIFF file and the .pfi file used to generate it.

And here is a screenshot showing the values of a color sampler placed on the bright reflection: