Why screenshot of same content appears more saturated on iPad 3 retina vs. Macbook Air LCD?
You could, but how would you know which is correct?

You would need accurate profiles for both screens. This could be done with colorimeter hardware/software, something like ColorMunki (No affiliation, it's just what I use myself), which can calibrate both your Mac &amp; iPad screens [also PCs, if you have them]

An app like Photoshop [&amp; possibly Gimp, though I've never used it] could then do the translation between the two, though once your screens are correctly calibrated, you may not need to.