[judk]

Do you map a 3D scene into 2D without any information about which aspect of the scene is important?

[tormeh]

That's not the same. When you go from 3D to 2D you lose a dimension. Information is lost. When you map color spaces like I proposed you go from 1D to 1D, you're just compressing the data in that dimension. No information is lost (except because of the limits of numerical accuracy)