What is "scrgb"

scRGB is a wide color gamut RGB (Red Green Blue) color space created by Microsoft and HP that uses the same color primaries and white/black points as the sRGB color space but allows coordinates below zero and greater than one. The full range is -0.5 through just less than +7.5.

Negative numbers enables scRGB to encompass most of the CIE 1931 color space while maintaining simplicity and backward compatibility with sRGB without the complexity of color management. The cost of maintaining compatibility with sRGB is that approximately 80% of the scRGB color space consists of imaginary colors.

Large positive numbers allow high dynamic range images to be represented, though the range is inferior to that of some other high dynamic range formats such as OpenEXR.