We deliberately only provide PPF values, not PPFD values. The PPF value describes the light output of the lamp for which we are responsible. This value varies depending on the chips installed, their number and the driver settings. Although we do not believe that the PPF value is a good indicator of the quality of a lamp (see above), it has become common practice to provide this value and our customers expect this from us. The PPFD value, on the other hand, describes the actual amount of light at the measuring point and is influenced by many factors that we cannot control. Different measuring environments, reflections and measuring methods lead to varying values. When we issue PPFD values, this is usually only done for specific purposes and with precise information about the measuring method.