The primary differences are: Temperature compatibility – Matte Tin is compatible with the elevated temperatures of lead-free, reflow processing (250-260C). Bright Tin has a tendency to discolor (turn dark) when exposed to the higher lead-free, reflow processing environment. Grain size – Matte Tin has a larger grain size than Bright Tin. Appearance – Matte Tin has a normal whitish “matte” surface appearance whereas Bright Tin has a bright (shiny) surface finish.