UniWB and ETTR with (Pentax K-30)


About UniWB and ETTR

Although UniWB (Unit White Balance) and ETTR (Expose to the Right) are technically two different subject matters they are tightly related, therefore I have lumped them together. UniWB deals with "forcing" the camera to present a "truthful" histogram for the individual RGB channels, not skewed by the white balance channel multipliers (which most often than not give the impression that the red and blue channels are overexposed, meanwhile they are in fact underexposed by half up-to a full stop). ETTR is a technique, usable only when the scene's contrast is lower than the camera's exposure range (colloquially called "dynamic range"), that allows the photographer to take advantage of the camera's full exposure range (or exposure latitude), by overexposing the scene just before the highlights are not overexposed (i.e. blown-out to complete white). Therefore a "truthful" histogram for the individual RGB channels is essential for ETTR, which in turn implies having both UniWB and linear contrast curves.


Version 1.1

Version 1.0