The key is in the chemical difference between platinum-cure (addition cure) and tin-cure (condensation cure) silicone mould making rubbers. But how does this affect performance?
Rubber materials, especially Polyurethanes, can vary in shades due to quite a few factors. This is very normal! But does colour have effect on performance of the cured material?
When mould making or casting Silicones or Polyurethanes, cooler temperatures will slow down the curing process, while warmer temperatures will speed up it up.