Red Filter Trick Solves the Biggest Study Problem #LifeHacks #StudySecrets #Genius Color filters work by selectively absorbing or transmitting certain wavelengths of light based on the material’s molecular structure. When white light, which contains a full spectrum of visible wavelengths, passes through a colored filter, the filter absorbs most wavelengths except those that correspond to its own color, which it allows to pass through. For example, a red filter absorbs shorter wavelengths like bl