Pewter and bronze share different undertones. While bronze has warm undertones, pewter has cool undertones. Warm undertones work best with earthy colors, while cool undertone looks great with blue or white.
The finish of pewter and bronze spray paint are very different. Pewter has a gunmetal or dark silver finish, while bronze has a dark gold cast.
Spray Paint Finish
In addition to the color's natural finish, the spray paint you select will likely have its own finish. This has to do with the spray paint's formula, not the shades themselves, so select carefully. A matte finish will have a dull, shine-free look, while a glossy finish will have a creamy, shiny look. A metallic finish will have slight shimmer.
Dark surfaces will naturally take on a darker version of the color, while light or untreated wood will take on the true color.
Remember that any sort of faux wood will result in a crackle effect if spray painted. This can add a vintage-like feel. To achieve the truest color on real wood, sand and prime wood prior to spray painting.