＊a : Unless otherwise specified (see footnotes f and g), the Relative Quantum Yield of each fluorescent protein (QFP) was determined using the following equation : QFP = (Qfluo* FFP* ODfluo) / (Ffluo* ODFP), where F is the fluorescence and OD is the optical density of either the fluorescent protein (FP) or the reference fluorophore (fluo). ＊b : Unless otherwise specified (see footnotes f and g), the Molar Extinction Coefficient (ε) for each protein was determined as follows: A = εcl (Beer-Lambert law) or ε = A/c, where A = absorbance, c = concentration (determined by the Bradford Protein Assay), l = path length (1 cm). Each molar extinction coefficient was determined at the absorption maxima of its respective protein. ＊c : Brightness = (Quantum Yield) (Extinction Coefficient) ＊d : C.T.= Chroma Technologies ＊e : Shaner, N. C. et al. (2004) Nature Biotechnol. 22(12):1567-1572.