Did you every cut and color correct a video on your computer then watch it on TV and think, “Man it did did not look like this on my Mac!” Did you calibrate your monitor? The pros use a calibrated monitor and special equipment to get the blacks black and the whites white. We can get very close to this for a lot less money. Note: If you do a lot of photography you are going to want to do this also.
The tool looks like a little mouse that you plug in to you USB port, then you hang the device over your display. You run a program on your mac that detects where the device is hanging and then sends 256 colors to it in a fast sequence. When it is complete it will prompt you to alter your color setting for your monitor and show you the before and after look. You might be very surprised
X-Rite Eye-One Display LT
If you don’t want to spend the money I totally understand. But at least walk though the manual calibration utility that Apple provides. It will not be as good but it will be better than you have now if you never have done it You can find it under Displays in system preferences then choose Calibrate.