Batch White Balance Correction

Gray World assumes the scene averages to neutral grey and is the more robust choice across varied subject matter. White Patch treats the brightest unclipped region as neutral, which is more accurate when the frame genuinely contains something white and less so when it does not.

Already-clipped pixels are excluded from the White Patch estimate. Their true values were lost at capture, and including them biases the white point toward whichever channel saturated first.

The computed gains are normalised to preserve luminance, so white balance changes colour only. Brightness stays a separate step — that separation is what makes batch results predictable and lets each part be written out as a distinct XMP parameter.