Figure 7.

Biofilm quantification of outdoor-exposed coupons. Each column shows the mean of the modulus of $\sqrt{{\left(a^{\ast }\right)}^2+{\left(b^{\ast }\right)}^2+{\left(100-L^{\ast }\right)}^2}$ (n = 5). Zn and Cu mean Zn-coated coupons and Cu-coated coupons, respectively. Error bars show the standard deviation. Student’s t-test was performed between the SS400 coupons and Zn-coated coupons or SS400 coupons and Cu-coated coupons. P means the p-value.