(1) Background: The use of light-emitting diode (LED) lighting is increasingly replacing traditional light sources in museums. There is a need to anticipate the damage caused by LED lighting to photographic prints. The aim of this study is to quantitatively predict fading on three inkjet color patches exposed to different white light LED; (2) Method: The novel approach of this work is to measure the wavelength-dependent photochemical efficiency on color patches using a narrow band LED. First, the color patches are exposed to narrow band LED lamps in a proprietary light chamber. Sensitivity curves are obtained by plotting the density changes caused by narrow band exposure as a function of the exposure. In the second step, action spectra are derived from the slopes of the sensitivity curves. The action spectra correspond to the rates of change of a color patch to exposure with different wavelengths of light. In the third step, the narrow band light emissions are fitted to the emission spectra of the white LED of interest. The fitting factors are used to calculate the weighted sum of the density changes; (3) The method predicts the absolute density change of color patches for several white light LED exposures.
