The idea is simple:
- Take a RAW photo of a real color chart outside to get a white point of D65.
- Use that to get an accurate color correction matrix for the camera sensor.
- Use the same camera to take a picture of the chart as displayed on the screen.
- Find the color correction matrix of the monitor, and load it into an ICC profile
In theory this be a fast way to get the correct color correction matrix of a monitor, with only a DSLR and a chart, and without additional expensive hardware.
So, what aspect of calibration am I missing?