Depths, Banding and Normal Maps

yeah but if you convert it to 8bit tga it become like in the image below.

2c04731cd95593da82d7ce293f3019d3c7b1578b.jpeg

it become noise effect, and not clean as Tiff 16bit

just wondering if there is a way to make it clean as Tiff16 , or people use this method and its fine?