Pastel colours for charts

[hh]

Recently I tested a lot with colors and color models, had no problems with that, but different results on an somewhat older LCD. May be this is a problem of your display (or it's calibration)? Some displays appear to be 'darker' at top 20%.

Did you try to compare this effect with a tool like "DigitalColor Meter"? At about the same loc of your display?
Or, as a next step, using "ColorSync Utility"?

Hermann