A UV filter prevents colour shifts and unsharpness due to UV radiation. An interlayer prevents the diffusion of unwanted colour dyes form one sensitive layer into another. So, the colours are well separated and the colour saturation is very good. Aviphot Chrome 200 is suitable for a colour temperature of 5500K.
It is old in the meaning of a late emulsion they used in their consumer range being used in their aerial range too.