The first fluorescent lighting systems used a single phosphor coating inside the lamp and produced a cool white light. The three phosphors produce light in the red, blue and green regions of the visible spectrum, giving white light when blended together. Incandescent lamps have a CRI of 97. Incandescent lamps provide excellent colour rendering because of the full spectrum of colour wavelengths present in the light they produce. The ambient temperature around a CF lamp can have a significant effect on light output and lamp efficacy.
Low temperatures pose the greatest problems for CF lamps.
Not all compact fluorescent systems are equally susceptible to low-temperature problems, but in general, as temperature drops, so does light output and efficacy. It is important to note that some CF lamps will have to warm up a while before producing sufficient light under cold conditions, some may take several minutes to ignite, and some won't start at all. These lamps are usually equipped with electronic ballasts and can be enclosed in globes or recesses to prevent wind chill of the lamp. Even with these precautions, it should not be assumed that the lamp will operate at the same efficiency and produce the same amount of light as it would under more hospitable weather conditions. Spectral sensitivities of photometer and eye compared to CFL output.