Polycarbonate Sheet Cross Sections below, Clear and Softlite offer high light & solar transmission, Softlite has 100% diffusion, for growing and privacy. White/Opal best choice for shade and cooling. The thicker the poly the higher the R-Value (insulation) and greater strength. Bronze gets hot in the sun, it transfers heat and the sheet expands and contracts a lot. Bronze is seldom used, as the transferred heat and dramatic expansion can cause issues.