For conducting an analysis as you want you must fold the colour within the actual solar power spectrum. An accurate analysis would involve the knowledge of the actual reflectance spectra of the coloured wraps, and of course matching thermal property and fit to the canister.

Note that the solar power impinging to your canister isn't constant all along the colours and, in addition to this, what we call colour has different bandwidths.

You can see that something looking blue absorbs more energy from the sun than a red counterpart by looking at this:

Taken from https://bit.ly/2LyxMhP

For conducting an analysis as you want you must fold the colour within the actual solar power spectrum. An accurate analysis would involve the knowledge of the actual reflectance spectra of the coloured wraps, and of course matching thermal property and fit to the canister.

Note that the solar power impinging to your canister isn't constant all along the colours and, in addition to this, what we call colour has different bandwidths.

You can see that something looking blue absorbs more energy from the sun than a red counterpart by looking at the solar irradiance (power versus colour, basically):

Taken from https://bit.ly/2LyxMhP