At lower levels, the human perception of reduced brightness as a percentage is provided by the following formula: perceived reduction % = 100 × actual reduction % 100 {\displaystyle {\text{perceived reduction}}\%=100\times {\sqrt {{\text{actual reduction}}\% \over 100}}} When the actual reduction is 1.00 / 1.30, or about 0.770, the perceived reduction is about 0.877, or 1.00 / 1.14.
La niveluri mai scăzute, percepția umană a reducerii strălucirii ca procentaj este dată de formula: reducere percepută % = 100 × reducere efectivă % 100 {\displaystyle {\text{reducere percepută}}\%=100\times {\sqrt {{\text{reducere efectivă}}\% \over 100}}} Când reducerea reală este de 1,00 / 1,30, sau de circa 0,770, reducerea percepută este de 0,877, sau de 1,00 / 1,14.