Simple filters but quality, with a wide range of colors, although the color scheme correspondence with 6 basic colors remains approximate. It would have been interesting for non-photographic use, which is indicated for each filter roughly the value of the dominant wavelength (knowing that the bandwidths are very large with this type of filter that is not interference !). In addition, very thin filters lack rigidity. However, careful storage of the filters in a well-designed protective pouch.