Glass Inspector controls the anisotropy, birefringence or also known as iridescence or leopard spots, of each of the glasses produced by its tempering oven under the American standard ASTM C1901-21, published in 2021 and in which it is defined as The anisotropy must be measured in tempered glass.
Glass Inspector 4D, through the procedure of measuring the delay of light that passes through the glass once tempered, evaluates the amount of anisotropy existing in the glass, rating it in 3 categories,