The Schneider Series 9 White Frost Filter is primarily a picture styling, or mood modifying tool. It subtly "flares" highlights and very slightly tones down contrast, while having no effect on image resolution or color reproduction.
This filter is very useful for adding a "halo" around light sources, "blown windows," or any other area of high exposure. It can also be used to reduce picture contrast by lowering white exposure, and can help you create a romantic or "period" look.
It enhances a scene, subtly or strongly, without reducing image resolution. If you prefer a softened, romantic image, it can be combined with a Schneider Classic Soft filter.