Template:Glapi srgb equation

$c_{l}={\begin{cases}{\tfrac {c_{s}}{12.92}},&{\text{if }}c_{s}\leq 0.04045\\\left({\tfrac {c_{s}+0.055}{1.055}}\right)^{2.4},&{\text{if }}c_{s}>0.04045\end{cases}}$