HDR Match

Sets an HDR shot's level to the plate it is composited onto. SDR to HDR picks its own exposure and white balance, while the plate's untouched pixels hold the scene's real values: one gain per channel, measured on the untouched mid-tones over the whole shot (no flicker), scales every pixel. A gain keeps every ratio, so the range SDR to HDR made above the plate's white stays for grading. Without an HDR shot the image passes through; without a matte the HDR shot does.