Two ultraviolet filters of polyester film, one colorless and one with a strong yellow color, were evaluated for their effectiveness in reducing fading of wool dyed with selected natural dyes and one synthetic dye. Results showed that clear filters offer no protection against fading for some natural dyes. Therefore, clear filters should not be regarded as a slightly less effective alternative to yellow filters for the protection from fading of museum artifacts colored with natural dyes because, in some instances, they are totally ineffective. When the use of yellow filters is unacceptable because of their distortion of color in exhibition areas, controlling level of illuminance to 50 lux is more beneficial than the use of clear filters in protecting some natural dyes from fading.