|In this study, electroluminescent panels manufactured by Meadow River Enterprises were used to study the AC frequency dependence of their color. A project was developed to acquire their emittance color at various frequencies. Three frequencies were selected for the investigation. Data, obtained by measuring the spectrum at a constant excitation frequency, were taken for each of the three standard frequencies: 200 Hz, 1500 Hz, and 20 kHz. In general the higher the frequency, the bluer the emittance color of the panel. The lower the frequency, the more green the panel became. An explanation for this phenomenon, the frequency dependence of the emission color, is suggested using a model for the electronic structure of Cu doped ZnS. It can be concluded that the blue emission is a two step process, while the green emission is a one step process according to the model used in this project.