BLUE & RED Version


The color of light emitted by the primary LED distinguishes the BLUE from the RED version of the DIVING-PAM-II fluorometer (Fig. 1). The BLUE version (DIVING-PAM-II/B) possesses a blue LED emitting maximally around 475 nm which is replaced by a red LED emitting maximally around 655 nm in the RED version (DIVING-PAM-II/R). Both versions have a second LED providing far red light for specific excitation of photosystem I.

The second difference between the two versions is the spectral window for fluorescence detection. The BLUE version detects fluorescence at wavelengths > 630 nm but the RED version detects fluorescence at wavelengths > 700 nm (Fig. 2).