Silver film vs. White paint
>You might find that just using a white material will work as well as a
>metallic one. White paint gives virtually the same amount (%) of
>reflectivity as a mirror.
Reflectors Approximate Light Level
White paint (old) 100%
White paint (new) 105-120%
Anodized aluminum 110-140%
Silver film 120-150%
Enhanced aluminum 120-150%
All ballast factors are 0.94.
Optical system or reflector modifications may change illumination uniformity.
Source for table: Advanced Lighting Guidelines and manufacturer test data.