Red and green are under-represented in the greyscale, and blue is over-represented. The gamma value of 2.1 does get very close to the desired value of 2.2. The colour range is much too narrow, and green deviates the least with a DeltaE of around 7. Ideally this is around 3, and the upper limit is really 5. The other colours deviate too much with values of above 10. The brightness of blue and magenta is too high, while green and yellow aren't bright enough.